<?xml version="1.0" encoding="UTF-8"?>

<!--XBRL Document Created with the Workiva Platform-->
<!--Copyright 2026 Workiva-->
<!--r:019e64ea-061c-74c6-be29-7a1d60bbb855,g:28d534a8-847d-4a7f-8087-c4c968d633fb-->
<link:linkbase xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd">
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/all" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#all"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#hypercube-dimension"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-default"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-domain"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/domain-member" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#domain-member"/>
  <link:roleRef roleURI="http://www.comscore.com/role/CONDENSEDCONSOLIDATEDBALANCESHEETS" xlink:type="simple" xlink:href="scor-20260630.xsd#CONDENSEDCONSOLIDATEDBALANCESHEETS"/>
  <link:definitionLink xlink:role="http://www.comscore.com/role/CONDENSEDCONSOLIDATEDBALANCESHEETS" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_019e64ea-07eb-7694-932b-9e07b853707e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_019e64ea-07eb-770b-9d01-bdc288f2c996" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_019e64ea-07eb-7694-932b-9e07b853707e" xlink:to="loc_us-gaap_StatementTable_019e64ea-07eb-770b-9d01-bdc288f2c996" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019e64ea-07eb-7921-9f54-c7cb6d5900ef" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_019e64ea-07eb-770b-9d01-bdc288f2c996" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019e64ea-07eb-7921-9f54-c7cb6d5900ef" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_019e64ea-07eb-7921-9f54-c7cb6d5900ef_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019e64ea-07eb-7921-9f54-c7cb6d5900ef" xlink:to="loc_us-gaap_RelatedPartyDomain_019e64ea-07eb-7921-9f54-c7cb6d5900ef_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_019e64ea-07eb-7162-96da-3a477ffd3acd" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019e64ea-07eb-7921-9f54-c7cb6d5900ef" xlink:to="loc_us-gaap_RelatedPartyDomain_019e64ea-07eb-7162-96da-3a477ffd3acd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyMember_019e64ea-07eb-75e9-9f49-d7d2463462f4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_019e64ea-07eb-7162-96da-3a477ffd3acd" xlink:to="loc_us-gaap_RelatedPartyMember_019e64ea-07eb-75e9-9f49-d7d2463462f4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NonrelatedPartyMember_019e64ea-07eb-7ab8-ad76-8bbaa700f5ee" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NonrelatedPartyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_019e64ea-07eb-7162-96da-3a477ffd3acd" xlink:to="loc_us-gaap_NonrelatedPartyMember_019e64ea-07eb-7ab8-ad76-8bbaa700f5ee" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsAbstract_019e64ea-07eb-715c-b8f4-bd3af4c3257e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetsAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e64ea-07eb-7694-932b-9e07b853707e" xlink:to="loc_us-gaap_AssetsAbstract_019e64ea-07eb-715c-b8f4-bd3af4c3257e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsCurrentAbstract_019e64ea-07eb-7d89-ba01-19f76e26b5dd" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetsCurrentAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_019e64ea-07eb-715c-b8f4-bd3af4c3257e" xlink:to="loc_us-gaap_AssetsCurrentAbstract_019e64ea-07eb-7d89-ba01-19f76e26b5dd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_019e64ea-07eb-774e-8616-fcff5e73357b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_019e64ea-07eb-7d89-ba01-19f76e26b5dd" xlink:to="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_019e64ea-07eb-774e-8616-fcff5e73357b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedCashAndCashEquivalentsAtCarryingValue_019e64ea-07eb-7f9f-87e8-17f10e6a4278" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RestrictedCashAndCashEquivalentsAtCarryingValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_019e64ea-07eb-7d89-ba01-19f76e26b5dd" xlink:to="loc_us-gaap_RestrictedCashAndCashEquivalentsAtCarryingValue_019e64ea-07eb-7f9f-87e8-17f10e6a4278" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsReceivableNetCurrent_019e64ea-07eb-7755-8e43-42af1e435875" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccountsReceivableNetCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_019e64ea-07eb-7d89-ba01-19f76e26b5dd" xlink:to="loc_us-gaap_AccountsReceivableNetCurrent_019e64ea-07eb-7755-8e43-42af1e435875" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PrepaidExpenseAndOtherAssetsCurrent_019e64ea-07eb-7246-9b23-d680f9558305" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PrepaidExpenseAndOtherAssetsCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_019e64ea-07eb-7d89-ba01-19f76e26b5dd" xlink:to="loc_us-gaap_PrepaidExpenseAndOtherAssetsCurrent_019e64ea-07eb-7246-9b23-d680f9558305" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsCurrent_019e64ea-07eb-7323-bdf1-e46fa47f5a4c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetsCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_019e64ea-07eb-7d89-ba01-19f76e26b5dd" xlink:to="loc_us-gaap_AssetsCurrent_019e64ea-07eb-7323-bdf1-e46fa47f5a4c" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAfterAccumulatedDepreciationAndAmortization_019e64ea-07eb-7f2a-af4e-8bc392d1b9b3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAfterAccumulatedDepreciationAndAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_019e64ea-07eb-715c-b8f4-bd3af4c3257e" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAfterAccumulatedDepreciationAndAmortization_019e64ea-07eb-7f2a-af4e-8bc392d1b9b3" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseRightOfUseAsset_019e64ea-07eb-79b1-9759-0740b5088f72" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingLeaseRightOfUseAsset"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_019e64ea-07eb-715c-b8f4-bd3af4c3257e" xlink:to="loc_us-gaap_OperatingLeaseRightOfUseAsset_019e64ea-07eb-79b1-9759-0740b5088f72" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredIncomeTaxAssetsNet_019e64ea-07eb-7256-a6e2-88effab86112" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DeferredIncomeTaxAssetsNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_019e64ea-07eb-715c-b8f4-bd3af4c3257e" xlink:to="loc_us-gaap_DeferredIncomeTaxAssetsNet_019e64ea-07eb-7256-a6e2-88effab86112" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsNet_019e64ea-07eb-77a4-9b38-1972a74c7650" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FiniteLivedIntangibleAssetsNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_019e64ea-07eb-715c-b8f4-bd3af4c3257e" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsNet_019e64ea-07eb-77a4-9b38-1972a74c7650" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Goodwill_019e64ea-07eb-7d8d-ace5-be05602d1753" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_Goodwill"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_019e64ea-07eb-715c-b8f4-bd3af4c3257e" xlink:to="loc_us-gaap_Goodwill_019e64ea-07eb-7d8d-ace5-be05602d1753" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherAssetsNoncurrent_019e64ea-07eb-774f-9e01-de53dedbb029" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherAssetsNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_019e64ea-07eb-715c-b8f4-bd3af4c3257e" xlink:to="loc_us-gaap_OtherAssetsNoncurrent_019e64ea-07eb-774f-9e01-de53dedbb029" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Assets_019e64ea-07eb-7fc5-bfba-e0872d205f69" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_Assets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_019e64ea-07eb-715c-b8f4-bd3af4c3257e" xlink:to="loc_us-gaap_Assets_019e64ea-07eb-7fc5-bfba-e0872d205f69" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_019e64ea-07eb-7f4d-b77b-c88e10b9dd89" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LiabilitiesAndStockholdersEquityAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e64ea-07eb-7694-932b-9e07b853707e" xlink:to="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_019e64ea-07eb-7f4d-b77b-c88e10b9dd89" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesCurrentAbstract_019e64ea-07eb-728f-a5e3-0da2a2186047" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LiabilitiesCurrentAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_019e64ea-07eb-7f4d-b77b-c88e10b9dd89" xlink:to="loc_us-gaap_LiabilitiesCurrentAbstract_019e64ea-07eb-728f-a5e3-0da2a2186047" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsPayableCurrent_019e64ea-07eb-7c09-8e3f-f985a2d8bba8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccountsPayableCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_019e64ea-07eb-728f-a5e3-0da2a2186047" xlink:to="loc_us-gaap_AccountsPayableCurrent_019e64ea-07eb-7c09-8e3f-f985a2d8bba8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccruedLiabilitiesCurrent_019e64ea-07eb-7d7a-b7df-0dda4e375c9a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccruedLiabilitiesCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_019e64ea-07eb-728f-a5e3-0da2a2186047" xlink:to="loc_us-gaap_AccruedLiabilitiesCurrent_019e64ea-07eb-7d7a-b7df-0dda4e375c9a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerLiabilityCurrent_019e64ea-07eb-70a0-a75b-32035965aea9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ContractWithCustomerLiabilityCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_019e64ea-07eb-728f-a5e3-0da2a2186047" xlink:to="loc_us-gaap_ContractWithCustomerLiabilityCurrent_019e64ea-07eb-70a0-a75b-32035965aea9" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_ContractWithCustomerLiabilityCustomerAdvancesCurrent_019e64ea-07eb-7d79-b177-a169d7f4a2bf" xlink:href="scor-20260630.xsd#scor_ContractWithCustomerLiabilityCustomerAdvancesCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_019e64ea-07eb-728f-a5e3-0da2a2186047" xlink:to="loc_scor_ContractWithCustomerLiabilityCustomerAdvancesCurrent_019e64ea-07eb-7d79-b177-a169d7f4a2bf" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseLiabilityCurrent_019e64ea-07eb-7013-a3ab-2cae309ada39" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingLeaseLiabilityCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_019e64ea-07eb-728f-a5e3-0da2a2186047" xlink:to="loc_us-gaap_OperatingLeaseLiabilityCurrent_019e64ea-07eb-7013-a3ab-2cae309ada39" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherLiabilitiesCurrent_019e64ea-07eb-7259-b9ea-7628a551f01c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherLiabilitiesCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_019e64ea-07eb-728f-a5e3-0da2a2186047" xlink:to="loc_us-gaap_OtherLiabilitiesCurrent_019e64ea-07eb-7259-b9ea-7628a551f01c" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesCurrent_019e64ea-07eb-7ef9-b0dd-798d47692c4b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LiabilitiesCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_019e64ea-07eb-728f-a5e3-0da2a2186047" xlink:to="loc_us-gaap_LiabilitiesCurrent_019e64ea-07eb-7ef9-b0dd-798d47692c4b" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtNoncurrent_019e64ea-07eb-7762-9603-680f6a675745" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongTermDebtNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_019e64ea-07eb-7f4d-b77b-c88e10b9dd89" xlink:to="loc_us-gaap_LongTermDebtNoncurrent_019e64ea-07eb-7762-9603-680f6a675745" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseLiabilityNoncurrent_019e64ea-07eb-7ca6-8b38-2e44389b2f48" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingLeaseLiabilityNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_019e64ea-07eb-7f4d-b77b-c88e10b9dd89" xlink:to="loc_us-gaap_OperatingLeaseLiabilityNoncurrent_019e64ea-07eb-7ca6-8b38-2e44389b2f48" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_AccruedCostOfRevenuesNoncurrent_019e64ea-07eb-7c31-8144-0509605d6d09" xlink:href="scor-20260630.xsd#scor_AccruedCostOfRevenuesNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_019e64ea-07eb-7f4d-b77b-c88e10b9dd89" xlink:to="loc_scor_AccruedCostOfRevenuesNoncurrent_019e64ea-07eb-7c31-8144-0509605d6d09" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredIncomeTaxLiabilitiesNet_019e64ea-07eb-75bd-a585-def057d832d7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DeferredIncomeTaxLiabilitiesNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_019e64ea-07eb-7f4d-b77b-c88e10b9dd89" xlink:to="loc_us-gaap_DeferredIncomeTaxLiabilitiesNet_019e64ea-07eb-75bd-a585-def057d832d7" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherLiabilitiesNoncurrent_019e64ea-07eb-74dc-8902-fa5727e7cd71" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherLiabilitiesNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_019e64ea-07eb-7f4d-b77b-c88e10b9dd89" xlink:to="loc_us-gaap_OtherLiabilitiesNoncurrent_019e64ea-07eb-74dc-8902-fa5727e7cd71" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Liabilities_019e64ea-07eb-7ecf-8077-b692008b89db" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_Liabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_019e64ea-07eb-7f4d-b77b-c88e10b9dd89" xlink:to="loc_us-gaap_Liabilities_019e64ea-07eb-7ecf-8077-b692008b89db" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommitmentsAndContingencies_019e64ea-07eb-76ae-bbd0-4e0f4cabef93" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommitmentsAndContingencies"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_019e64ea-07eb-7f4d-b77b-c88e10b9dd89" xlink:to="loc_us-gaap_CommitmentsAndContingencies_019e64ea-07eb-76ae-bbd0-4e0f4cabef93" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TemporaryEquityCarryingAmountAttributableToParent_019e64ea-07eb-72ce-9993-bfc74ddc089a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TemporaryEquityCarryingAmountAttributableToParent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_019e64ea-07eb-7f4d-b77b-c88e10b9dd89" xlink:to="loc_us-gaap_TemporaryEquityCarryingAmountAttributableToParent_019e64ea-07eb-72ce-9993-bfc74ddc089a" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityAbstract_019e64ea-07eb-7b16-8418-5d7a0ce06d33" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockholdersEquityAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_019e64ea-07eb-7f4d-b77b-c88e10b9dd89" xlink:to="loc_us-gaap_StockholdersEquityAbstract_019e64ea-07eb-7b16-8418-5d7a0ce06d33" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockValue_019e64ea-07eb-76ef-9c3d-4d63c023e37f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PreferredStockValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_019e64ea-07eb-7b16-8418-5d7a0ce06d33" xlink:to="loc_us-gaap_PreferredStockValue_019e64ea-07eb-76ef-9c3d-4d63c023e37f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockValue_019e64ea-07eb-7536-a5f8-bd195d2371b9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_019e64ea-07eb-7b16-8418-5d7a0ce06d33" xlink:to="loc_us-gaap_CommonStockValue_019e64ea-07eb-7536-a5f8-bd195d2371b9" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdditionalPaidInCapitalCommonStock_019e64ea-07eb-7f7c-a708-f96378ffeee8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AdditionalPaidInCapitalCommonStock"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_019e64ea-07eb-7b16-8418-5d7a0ce06d33" xlink:to="loc_us-gaap_AdditionalPaidInCapitalCommonStock_019e64ea-07eb-7f7c-a708-f96378ffeee8" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_019e64ea-07eb-7cdd-9de5-2577c9b91097" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_019e64ea-07eb-7b16-8418-5d7a0ce06d33" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_019e64ea-07eb-7cdd-9de5-2577c9b91097" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetainedEarningsAccumulatedDeficit_019e64ea-07eb-7f36-a0d0-842366991b65" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RetainedEarningsAccumulatedDeficit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_019e64ea-07eb-7b16-8418-5d7a0ce06d33" xlink:to="loc_us-gaap_RetainedEarningsAccumulatedDeficit_019e64ea-07eb-7f36-a0d0-842366991b65" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TreasuryStockCommonValue_019e64ea-07eb-75bb-9731-f48ac95ac843" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TreasuryStockCommonValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_019e64ea-07eb-7b16-8418-5d7a0ce06d33" xlink:to="loc_us-gaap_TreasuryStockCommonValue_019e64ea-07eb-75bb-9731-f48ac95ac843" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_019e64ea-07eb-728c-b99b-848bdfa98300" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockholdersEquity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_019e64ea-07eb-7b16-8418-5d7a0ce06d33" xlink:to="loc_us-gaap_StockholdersEquity_019e64ea-07eb-728c-b99b-848bdfa98300" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquity_019e64ea-07eb-7fea-b9bc-5695b98f935c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LiabilitiesAndStockholdersEquity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_019e64ea-07eb-7f4d-b77b-c88e10b9dd89" xlink:to="loc_us-gaap_LiabilitiesAndStockholdersEquity_019e64ea-07eb-7fea-b9bc-5695b98f935c" xlink:type="arc" order="11"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.comscore.com/role/CONDENSEDCONSOLIDATEDBALANCESHEETSParenthetical" xlink:type="simple" xlink:href="scor-20260630.xsd#CONDENSEDCONSOLIDATEDBALANCESHEETSParenthetical"/>
  <link:definitionLink xlink:role="http://www.comscore.com/role/CONDENSEDCONSOLIDATEDBALANCESHEETSParenthetical" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_019e64ea-07eb-7b73-babf-739b79c597d3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_019e64ea-07eb-741b-a308-95945152c6bc" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_019e64ea-07eb-7b73-babf-739b79c597d3" xlink:to="loc_us-gaap_StatementTable_019e64ea-07eb-741b-a308-95945152c6bc" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019e64ea-07eb-7559-ace2-4a9574073b92" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_019e64ea-07eb-741b-a308-95945152c6bc" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019e64ea-07eb-7559-ace2-4a9574073b92" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_019e64ea-07eb-7559-ace2-4a9574073b92_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019e64ea-07eb-7559-ace2-4a9574073b92" xlink:to="loc_us-gaap_RelatedPartyDomain_019e64ea-07eb-7559-ace2-4a9574073b92_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_019e64ea-07eb-7950-8992-7074cf3c0537" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019e64ea-07eb-7559-ace2-4a9574073b92" xlink:to="loc_us-gaap_RelatedPartyDomain_019e64ea-07eb-7950-8992-7074cf3c0537" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyMember_019e64ea-07eb-7210-ad72-7fd5d313959d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_019e64ea-07eb-7950-8992-7074cf3c0537" xlink:to="loc_us-gaap_RelatedPartyMember_019e64ea-07eb-7210-ad72-7fd5d313959d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementClassOfStockAxis_019e64ea-07eb-7b36-8bcd-2fc1255746a8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementClassOfStockAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_019e64ea-07eb-741b-a308-95945152c6bc" xlink:to="loc_us-gaap_StatementClassOfStockAxis_019e64ea-07eb-7b36-8bcd-2fc1255746a8" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_019e64ea-07eb-7b36-8bcd-2fc1255746a8_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_019e64ea-07eb-7b36-8bcd-2fc1255746a8" xlink:to="loc_us-gaap_ClassOfStockDomain_019e64ea-07eb-7b36-8bcd-2fc1255746a8_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_019e64ea-07eb-764d-a0ba-726b8f8a36cb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_019e64ea-07eb-7b36-8bcd-2fc1255746a8" xlink:to="loc_us-gaap_ClassOfStockDomain_019e64ea-07eb-764d-a0ba-726b8f8a36cb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_SeriesCRedeemableConvertiblePreferredStockMember_019e64ea-07eb-76c2-a17b-7517aa849e30" xlink:href="scor-20260630.xsd#scor_SeriesCRedeemableConvertiblePreferredStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_019e64ea-07eb-764d-a0ba-726b8f8a36cb" xlink:to="loc_scor_SeriesCRedeemableConvertiblePreferredStockMember_019e64ea-07eb-76c2-a17b-7517aa849e30" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsAbstract_019e64ea-07eb-78ac-a637-2f5c0d398ebd" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetsAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e64ea-07eb-7b73-babf-739b79c597d3" xlink:to="loc_us-gaap_AssetsAbstract_019e64ea-07eb-78ac-a637-2f5c0d398ebd" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsCurrentAbstract_019e64ea-07eb-738f-b50f-d3ea845bed0f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetsCurrentAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_019e64ea-07eb-78ac-a637-2f5c0d398ebd" xlink:to="loc_us-gaap_AssetsCurrentAbstract_019e64ea-07eb-738f-b50f-d3ea845bed0f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllowanceForDoubtfulAccountsReceivable_019e64ea-07eb-7c2a-8430-5b62428866b0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AllowanceForDoubtfulAccountsReceivable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_019e64ea-07eb-738f-b50f-d3ea845bed0f" xlink:to="loc_us-gaap_AllowanceForDoubtfulAccountsReceivable_019e64ea-07eb-7c2a-8430-5b62428866b0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsReceivableNetCurrent_019e64ea-07eb-7912-ae0f-2ff3e6a8450f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccountsReceivableNetCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_019e64ea-07eb-738f-b50f-d3ea845bed0f" xlink:to="loc_us-gaap_AccountsReceivableNetCurrent_019e64ea-07eb-7912-ae0f-2ff3e6a8450f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_019e64ea-07eb-70e4-86b0-cc662442aad2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LiabilitiesAndStockholdersEquityAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e64ea-07eb-7b73-babf-739b79c597d3" xlink:to="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_019e64ea-07eb-70e4-86b0-cc662442aad2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesCurrentAbstract_019e64ea-07eb-789b-9674-8a272643a60e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LiabilitiesCurrentAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_019e64ea-07eb-70e4-86b0-cc662442aad2" xlink:to="loc_us-gaap_LiabilitiesCurrentAbstract_019e64ea-07eb-789b-9674-8a272643a60e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsPayableCurrent_019e64ea-07eb-7808-ad36-ede809f6f34a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccountsPayableCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_019e64ea-07eb-789b-9674-8a272643a60e" xlink:to="loc_us-gaap_AccountsPayableCurrent_019e64ea-07eb-7808-ad36-ede809f6f34a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccruedLiabilitiesCurrent_019e64ea-07eb-783b-807f-65ddd1ebd05a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccruedLiabilitiesCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_019e64ea-07eb-789b-9674-8a272643a60e" xlink:to="loc_us-gaap_AccruedLiabilitiesCurrent_019e64ea-07eb-783b-807f-65ddd1ebd05a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerLiabilityCurrent_019e64ea-07eb-7071-9fd1-ffa42c9e0765" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ContractWithCustomerLiabilityCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_019e64ea-07eb-789b-9674-8a272643a60e" xlink:to="loc_us-gaap_ContractWithCustomerLiabilityCurrent_019e64ea-07eb-7071-9fd1-ffa42c9e0765" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_AccruedCostOfRevenuesNoncurrent_019e64ea-07eb-793b-94ed-58682a4d2090" xlink:href="scor-20260630.xsd#scor_AccruedCostOfRevenuesNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_019e64ea-07eb-789b-9674-8a272643a60e" xlink:to="loc_scor_AccruedCostOfRevenuesNoncurrent_019e64ea-07eb-793b-94ed-58682a4d2090" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TemporaryEquityParOrStatedValuePerShare_019e64ea-07eb-7eb8-be14-ab394dcdd4df" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TemporaryEquityParOrStatedValuePerShare"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_019e64ea-07eb-70e4-86b0-cc662442aad2" xlink:to="loc_us-gaap_TemporaryEquityParOrStatedValuePerShare_019e64ea-07eb-7eb8-be14-ab394dcdd4df" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TemporaryEquitySharesAuthorized_019e64ea-07eb-7f21-8c2c-f95bb57b5bf2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TemporaryEquitySharesAuthorized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_019e64ea-07eb-70e4-86b0-cc662442aad2" xlink:to="loc_us-gaap_TemporaryEquitySharesAuthorized_019e64ea-07eb-7f21-8c2c-f95bb57b5bf2" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TemporaryEquitySharesIssued_019e64ea-07eb-7824-86e8-6d93fc0cb287" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TemporaryEquitySharesIssued"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_019e64ea-07eb-70e4-86b0-cc662442aad2" xlink:to="loc_us-gaap_TemporaryEquitySharesIssued_019e64ea-07eb-7824-86e8-6d93fc0cb287" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TemporaryEquitySharesOutstanding_019e64ea-07eb-70dc-9a1e-1267e05df8c6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TemporaryEquitySharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_019e64ea-07eb-70e4-86b0-cc662442aad2" xlink:to="loc_us-gaap_TemporaryEquitySharesOutstanding_019e64ea-07eb-70dc-9a1e-1267e05df8c6" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TemporaryEquityLiquidationPreference_019e64ea-07eb-732c-93a0-0a99560f05e3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TemporaryEquityLiquidationPreference"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_019e64ea-07eb-70e4-86b0-cc662442aad2" xlink:to="loc_us-gaap_TemporaryEquityLiquidationPreference_019e64ea-07eb-732c-93a0-0a99560f05e3" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityAbstract_019e64ea-07eb-7f35-88e2-cc2702f6b82b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockholdersEquityAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_019e64ea-07eb-70e4-86b0-cc662442aad2" xlink:to="loc_us-gaap_StockholdersEquityAbstract_019e64ea-07eb-7f35-88e2-cc2702f6b82b" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockParOrStatedValuePerShare_019e64ea-07eb-7445-aea1-b0cc61b2e758" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PreferredStockParOrStatedValuePerShare"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_019e64ea-07eb-7f35-88e2-cc2702f6b82b" xlink:to="loc_us-gaap_PreferredStockParOrStatedValuePerShare_019e64ea-07eb-7445-aea1-b0cc61b2e758" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockSharesAuthorized_019e64ea-07eb-71c3-b784-ce942bb8a645" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PreferredStockSharesAuthorized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_019e64ea-07eb-7f35-88e2-cc2702f6b82b" xlink:to="loc_us-gaap_PreferredStockSharesAuthorized_019e64ea-07eb-71c3-b784-ce942bb8a645" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockSharesIssued_019e64ea-07eb-7144-9b98-9dc2c5ddd905" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PreferredStockSharesIssued"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_019e64ea-07eb-7f35-88e2-cc2702f6b82b" xlink:to="loc_us-gaap_PreferredStockSharesIssued_019e64ea-07eb-7144-9b98-9dc2c5ddd905" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockSharesOutstanding_019e64ea-07eb-7756-8a02-f2d1a7a9a596" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PreferredStockSharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_019e64ea-07eb-7f35-88e2-cc2702f6b82b" xlink:to="loc_us-gaap_PreferredStockSharesOutstanding_019e64ea-07eb-7756-8a02-f2d1a7a9a596" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockParOrStatedValuePerShare_019e64ea-07eb-7af8-ab64-57fb741d852f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockParOrStatedValuePerShare"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_019e64ea-07eb-7f35-88e2-cc2702f6b82b" xlink:to="loc_us-gaap_CommonStockParOrStatedValuePerShare_019e64ea-07eb-7af8-ab64-57fb741d852f" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesAuthorized_019e64ea-07eb-7ca8-87c2-e6cca6fc3166" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockSharesAuthorized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_019e64ea-07eb-7f35-88e2-cc2702f6b82b" xlink:to="loc_us-gaap_CommonStockSharesAuthorized_019e64ea-07eb-7ca8-87c2-e6cca6fc3166" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesIssued_019e64ea-07eb-76b9-b3ee-78a0d44aaca4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockSharesIssued"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_019e64ea-07eb-7f35-88e2-cc2702f6b82b" xlink:to="loc_us-gaap_CommonStockSharesIssued_019e64ea-07eb-76b9-b3ee-78a0d44aaca4" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesOutstanding_019e64ea-07eb-72dd-add6-85bfdf7d1044" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockSharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_019e64ea-07eb-7f35-88e2-cc2702f6b82b" xlink:to="loc_us-gaap_CommonStockSharesOutstanding_019e64ea-07eb-72dd-add6-85bfdf7d1044" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TreasuryStockCommonShares_019e64ea-07eb-7b9b-ac53-f63ec71a7384" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TreasuryStockCommonShares"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_019e64ea-07eb-7f35-88e2-cc2702f6b82b" xlink:to="loc_us-gaap_TreasuryStockCommonShares_019e64ea-07eb-7b9b-ac53-f63ec71a7384" xlink:type="arc" order="9"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.comscore.com/role/CONDENSEDCONSOLIDATEDSTATEMENTSOFOPERATIONSANDCOMPREHENSIVELOSSParenthetical" xlink:type="simple" xlink:href="scor-20260630.xsd#CONDENSEDCONSOLIDATEDSTATEMENTSOFOPERATIONSANDCOMPREHENSIVELOSSParenthetical"/>
  <link:definitionLink xlink:role="http://www.comscore.com/role/CONDENSEDCONSOLIDATEDSTATEMENTSOFOPERATIONSANDCOMPREHENSIVELOSSParenthetical" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_019e64ea-07eb-7e16-95f4-8184b1c5f6f2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_019e64ea-07eb-7bce-ba9d-491066a198bc" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_019e64ea-07eb-7e16-95f4-8184b1c5f6f2" xlink:to="loc_us-gaap_StatementTable_019e64ea-07eb-7bce-ba9d-491066a198bc" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019e64ea-07eb-71cc-9f4d-0539ee792f00" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_019e64ea-07eb-7bce-ba9d-491066a198bc" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019e64ea-07eb-71cc-9f4d-0539ee792f00" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_019e64ea-07eb-71cc-9f4d-0539ee792f00_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019e64ea-07eb-71cc-9f4d-0539ee792f00" xlink:to="loc_us-gaap_RelatedPartyDomain_019e64ea-07eb-71cc-9f4d-0539ee792f00_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_019e64ea-07eb-7223-a1eb-5450d8ae35e8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019e64ea-07eb-71cc-9f4d-0539ee792f00" xlink:to="loc_us-gaap_RelatedPartyDomain_019e64ea-07eb-7223-a1eb-5450d8ae35e8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyMember_019e64ea-07eb-7719-ba3a-74e6abc7db2b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_019e64ea-07eb-7223-a1eb-5450d8ae35e8" xlink:to="loc_us-gaap_RelatedPartyMember_019e64ea-07eb-7719-ba3a-74e6abc7db2b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementOfIncomeLocationBalanceAxis_019fc857-0007-7419-b855-799ee0e41e3d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementOfIncomeLocationBalanceAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_019e64ea-07eb-7bce-ba9d-491066a198bc" xlink:to="loc_us-gaap_StatementOfIncomeLocationBalanceAxis_019fc857-0007-7419-b855-799ee0e41e3d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_019e64ea-07eb-7b50-93d0-d3d28406b12a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e64ea-07eb-7e16-95f4-8184b1c5f6f2" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_019e64ea-07eb-7b50-93d0-d3d28406b12a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostOfGoodsAndServicesSold_019e64ea-07eb-7da5-8e39-370fb09b0a24" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CostOfGoodsAndServicesSold"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e64ea-07eb-7e16-95f4-8184b1c5f6f2" xlink:to="loc_us-gaap_CostOfGoodsAndServicesSold_019e64ea-07eb-7da5-8e39-370fb09b0a24" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RedeemablePreferredStockDividends_019e64ea-07eb-785c-b911-cbac9314e3e1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RedeemablePreferredStockDividends"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e64ea-07eb-7e16-95f4-8184b1c5f6f2" xlink:to="loc_us-gaap_RedeemablePreferredStockDividends_019e64ea-07eb-785c-b911-cbac9314e3e1" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllocatedShareBasedCompensationExpense_019e64ea-07eb-7dfb-88ae-601136e35eb4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AllocatedShareBasedCompensationExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e64ea-07eb-7e16-95f4-8184b1c5f6f2" xlink:to="loc_us-gaap_AllocatedShareBasedCompensationExpense_019e64ea-07eb-7dfb-88ae-601136e35eb4" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.comscore.com/role/CONDENSEDCONSOLIDATEDSTATEMENTSOFOPERATIONSANDCOMPREHENSIVELOSSParenthetical_1" xlink:type="simple" xlink:href="scor-20260630.xsd#CONDENSEDCONSOLIDATEDSTATEMENTSOFOPERATIONSANDCOMPREHENSIVELOSSParenthetical_1"/>
  <link:definitionLink xlink:role="http://www.comscore.com/role/CONDENSEDCONSOLIDATEDSTATEMENTSOFOPERATIONSANDCOMPREHENSIVELOSSParenthetical_1" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_019e64ea-07eb-7e16-95f4-8184b1c5f6f2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_019e64ea-07eb-7bce-ba9d-491066a198bc" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_019e64ea-07eb-7e16-95f4-8184b1c5f6f2" xlink:to="loc_us-gaap_StatementTable_019e64ea-07eb-7bce-ba9d-491066a198bc" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019e64ea-07eb-71cc-9f4d-0539ee792f00" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_019e64ea-07eb-7bce-ba9d-491066a198bc" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019e64ea-07eb-71cc-9f4d-0539ee792f00" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_019e64ea-07eb-71cc-9f4d-0539ee792f00_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019e64ea-07eb-71cc-9f4d-0539ee792f00" xlink:to="loc_us-gaap_RelatedPartyDomain_019e64ea-07eb-71cc-9f4d-0539ee792f00_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_019e64ea-07eb-7223-a1eb-5450d8ae35e8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019e64ea-07eb-71cc-9f4d-0539ee792f00" xlink:to="loc_us-gaap_RelatedPartyDomain_019e64ea-07eb-7223-a1eb-5450d8ae35e8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyMember_019e64ea-07eb-7719-ba3a-74e6abc7db2b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_019e64ea-07eb-7223-a1eb-5450d8ae35e8" xlink:to="loc_us-gaap_RelatedPartyMember_019e64ea-07eb-7719-ba3a-74e6abc7db2b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_019e64ea-07eb-7b50-93d0-d3d28406b12a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e64ea-07eb-7e16-95f4-8184b1c5f6f2" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_019e64ea-07eb-7b50-93d0-d3d28406b12a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostOfGoodsAndServicesSold_019e64ea-07eb-7da5-8e39-370fb09b0a24" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CostOfGoodsAndServicesSold"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e64ea-07eb-7e16-95f4-8184b1c5f6f2" xlink:to="loc_us-gaap_CostOfGoodsAndServicesSold_019e64ea-07eb-7da5-8e39-370fb09b0a24" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RedeemablePreferredStockDividends_019e64ea-07eb-785c-b911-cbac9314e3e1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RedeemablePreferredStockDividends"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e64ea-07eb-7e16-95f4-8184b1c5f6f2" xlink:to="loc_us-gaap_RedeemablePreferredStockDividends_019e64ea-07eb-785c-b911-cbac9314e3e1" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllocatedShareBasedCompensationExpense_019e64ea-07eb-7dfb-88ae-601136e35eb4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AllocatedShareBasedCompensationExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e64ea-07eb-7e16-95f4-8184b1c5f6f2" xlink:to="loc_us-gaap_AllocatedShareBasedCompensationExpense_019e64ea-07eb-7dfb-88ae-601136e35eb4" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.comscore.com/role/CONDENSEDCONSOLIDATEDSTATEMENTSOFCONVERTIBLEREDEEMABLEPREFERREDSTOCKANDSTOCKHOLDERSEQUITYDEFICIT" xlink:type="simple" xlink:href="scor-20260630.xsd#CONDENSEDCONSOLIDATEDSTATEMENTSOFCONVERTIBLEREDEEMABLEPREFERREDSTOCKANDSTOCKHOLDERSEQUITYDEFICIT"/>
  <link:definitionLink xlink:role="http://www.comscore.com/role/CONDENSEDCONSOLIDATEDSTATEMENTSOFCONVERTIBLEREDEEMABLEPREFERREDSTOCKANDSTOCKHOLDERSEQUITYDEFICIT" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_019e64ea-07eb-7b8f-a9c0-964fec981e70" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_019e64ea-07eb-7b87-bc6e-9ea1a0176b85" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_019e64ea-07eb-7b8f-a9c0-964fec981e70" xlink:to="loc_us-gaap_StatementTable_019e64ea-07eb-7b87-bc6e-9ea1a0176b85" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_019e64ea-07eb-7efd-948f-43dce51bb643" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_019e64ea-07eb-7b87-bc6e-9ea1a0176b85" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_019e64ea-07eb-7efd-948f-43dce51bb643" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_019e64ea-07eb-7efd-948f-43dce51bb643_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_019e64ea-07eb-7efd-948f-43dce51bb643" xlink:to="loc_us-gaap_EquityComponentDomain_019e64ea-07eb-7efd-948f-43dce51bb643_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_019e64ea-07eb-728b-9fe6-2ac53bd363b2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_019e64ea-07eb-7efd-948f-43dce51bb643" xlink:to="loc_us-gaap_EquityComponentDomain_019e64ea-07eb-728b-9fe6-2ac53bd363b2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockMember_019e64ea-07eb-7f0b-a6d0-26724fe93d48" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_019e64ea-07eb-728b-9fe6-2ac53bd363b2" xlink:to="loc_us-gaap_CommonStockMember_019e64ea-07eb-7f0b-a6d0-26724fe93d48" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdditionalPaidInCapitalMember_019e64ea-07eb-728b-9c2d-8086815860a1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AdditionalPaidInCapitalMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_019e64ea-07eb-728b-9fe6-2ac53bd363b2" xlink:to="loc_us-gaap_AdditionalPaidInCapitalMember_019e64ea-07eb-728b-9c2d-8086815860a1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_019e64ea-07eb-7ad3-88df-e696d051ab2d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_019e64ea-07eb-728b-9fe6-2ac53bd363b2" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_019e64ea-07eb-7ad3-88df-e696d051ab2d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetainedEarningsMember_019e64ea-07eb-74fd-b4d9-28497e138788" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RetainedEarningsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_019e64ea-07eb-728b-9fe6-2ac53bd363b2" xlink:to="loc_us-gaap_RetainedEarningsMember_019e64ea-07eb-74fd-b4d9-28497e138788" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TreasuryStockCommonMember_019e64ea-07eb-79f8-8f1b-045772054b23" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TreasuryStockCommonMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_019e64ea-07eb-728b-9fe6-2ac53bd363b2" xlink:to="loc_us-gaap_TreasuryStockCommonMember_019e64ea-07eb-79f8-8f1b-045772054b23" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementClassOfStockAxis_019e64ea-07eb-70a3-917e-220cf66b7482" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementClassOfStockAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_019e64ea-07eb-7b87-bc6e-9ea1a0176b85" xlink:to="loc_us-gaap_StatementClassOfStockAxis_019e64ea-07eb-70a3-917e-220cf66b7482" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_019e64ea-07eb-70a3-917e-220cf66b7482_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_019e64ea-07eb-70a3-917e-220cf66b7482" xlink:to="loc_us-gaap_ClassOfStockDomain_019e64ea-07eb-70a3-917e-220cf66b7482_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_019e64ea-07eb-7a2a-a076-73d49f549413" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_019e64ea-07eb-70a3-917e-220cf66b7482" xlink:to="loc_us-gaap_ClassOfStockDomain_019e64ea-07eb-7a2a-a076-73d49f549413" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_SeriesCRedeemableConvertiblePreferredStockMember_019e64ea-07eb-754a-ac5f-88e6e9fcdf12" xlink:href="scor-20260630.xsd#scor_SeriesCRedeemableConvertiblePreferredStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_019e64ea-07eb-7a2a-a076-73d49f549413" xlink:to="loc_scor_SeriesCRedeemableConvertiblePreferredStockMember_019e64ea-07eb-754a-ac5f-88e6e9fcdf12" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_SeriesBRedeemableConvertiblePreferredStockMember_019e64ea-07eb-78f4-8236-db27e2595f51" xlink:href="scor-20260630.xsd#scor_SeriesBRedeemableConvertiblePreferredStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_019e64ea-07eb-7a2a-a076-73d49f549413" xlink:to="loc_scor_SeriesBRedeemableConvertiblePreferredStockMember_019e64ea-07eb-78f4-8236-db27e2595f51" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInTemporaryEquityRollForward_019e64ea-07eb-7aa0-9930-80ebee05a674" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncreaseDecreaseInTemporaryEquityRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e64ea-07eb-7b8f-a9c0-964fec981e70" xlink:to="loc_us-gaap_IncreaseDecreaseInTemporaryEquityRollForward_019e64ea-07eb-7aa0-9930-80ebee05a674" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TemporaryEquitySharesOutstanding_019e64ea-07eb-7598-9dcd-9f51d0a724c2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TemporaryEquitySharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInTemporaryEquityRollForward_019e64ea-07eb-7aa0-9930-80ebee05a674" xlink:to="loc_us-gaap_TemporaryEquitySharesOutstanding_019e64ea-07eb-7598-9dcd-9f51d0a724c2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TemporaryEquityCarryingAmountAttributableToParent_019e64ea-07eb-759c-83fb-47b7e929c2c9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TemporaryEquityCarryingAmountAttributableToParent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInTemporaryEquityRollForward_019e64ea-07eb-7aa0-9930-80ebee05a674" xlink:to="loc_us-gaap_TemporaryEquityCarryingAmountAttributableToParent_019e64ea-07eb-759c-83fb-47b7e929c2c9" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_TemporaryEquityAdjustmentToIssuanceCostsForRecapitalizationTransaction_019e64ea-07eb-7b3a-b174-81628ccfc905" xlink:href="scor-20260630.xsd#scor_TemporaryEquityAdjustmentToIssuanceCostsForRecapitalizationTransaction"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInTemporaryEquityRollForward_019e64ea-07eb-7aa0-9930-80ebee05a674" xlink:to="loc_scor_TemporaryEquityAdjustmentToIssuanceCostsForRecapitalizationTransaction_019e64ea-07eb-7b3a-b174-81628ccfc905" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TemporaryEquitySharesOutstanding_019e64ea-07eb-71ae-a2c7-ea73b3aa1bc0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TemporaryEquitySharesOutstanding"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TemporaryEquityCarryingAmountAttributableToParent_019e64ea-07eb-72ef-beeb-9ce07d0969ed" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TemporaryEquityCarryingAmountAttributableToParent"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e64ea-07eb-7bd5-8845-3c7c1a1144ad" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncreaseDecreaseInStockholdersEquityRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e64ea-07eb-7b8f-a9c0-964fec981e70" xlink:to="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e64ea-07eb-7bd5-8845-3c7c1a1144ad" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesOutstanding_019e64ea-07eb-73c5-a4aa-5cfa169c4afd" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockSharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e64ea-07eb-7bd5-8845-3c7c1a1144ad" xlink:to="loc_us-gaap_CommonStockSharesOutstanding_019e64ea-07eb-73c5-a4aa-5cfa169c4afd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_019e64ea-07eb-7a11-a51c-95ca3a206639" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockholdersEquity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e64ea-07eb-7bd5-8845-3c7c1a1144ad" xlink:to="loc_us-gaap_StockholdersEquity_019e64ea-07eb-7a11-a51c-95ca3a206639" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_019e64ea-07eb-7b7d-bbeb-4b4f38836a9e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e64ea-07eb-7bd5-8845-3c7c1a1144ad" xlink:to="loc_us-gaap_NetIncomeLoss_019e64ea-07eb-7b7d-bbeb-4b4f38836a9e" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DividendsPreferredStock_019e64ea-07eb-7304-984a-154ef08a6878" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DividendsPreferredStock"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e64ea-07eb-7bd5-8845-3c7c1a1144ad" xlink:to="loc_us-gaap_DividendsPreferredStock_019e64ea-07eb-7304-984a-154ef08a6878" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalStockIssuedIssuanceCosts_019e64ea-07eb-7c63-863f-d8d988459925" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AdjustmentsToAdditionalPaidInCapitalStockIssuedIssuanceCosts"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e64ea-07eb-7bd5-8845-3c7c1a1144ad" xlink:to="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalStockIssuedIssuanceCosts_019e64ea-07eb-7c63-863f-d8d988459925" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardGross_019e64ea-07eb-7df3-b560-d37ba71e5df1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e64ea-07eb-7bd5-8845-3c7c1a1144ad" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardGross_019e64ea-07eb-7df3-b560-d37ba71e5df1" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharesPaidForTaxWithholdingForShareBasedCompensation_019eb600-b116-7bb0-8ddf-cab1238504fb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SharesPaidForTaxWithholdingForShareBasedCompensation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e64ea-07eb-7bd5-8845-3c7c1a1144ad" xlink:to="loc_us-gaap_SharesPaidForTaxWithholdingForShareBasedCompensation_019eb600-b116-7bb0-8ddf-cab1238504fb" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsRelatedToTaxWithholdingForShareBasedCompensation_019eb600-b116-7352-b5a1-03dc62734856" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AdjustmentsRelatedToTaxWithholdingForShareBasedCompensation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e64ea-07eb-7bd5-8845-3c7c1a1144ad" xlink:to="loc_us-gaap_AdjustmentsRelatedToTaxWithholdingForShareBasedCompensation_019eb600-b116-7352-b5a1-03dc62734856" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_019e64ea-07eb-763d-b0f3-e2a71276382b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e64ea-07eb-7bd5-8845-3c7c1a1144ad" xlink:to="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_019e64ea-07eb-763d-b0f3-e2a71276382b" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalShareBasedCompensationRestrictedStockUnitsRequisiteServicePeriodRecognition_019e64ea-07eb-7687-acbf-669adc2be504" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AdjustmentsToAdditionalPaidInCapitalShareBasedCompensationRestrictedStockUnitsRequisiteServicePeriodRecognition"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e64ea-07eb-7bd5-8845-3c7c1a1144ad" xlink:to="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalShareBasedCompensationRestrictedStockUnitsRequisiteServicePeriodRecognition_019e64ea-07eb-7687-acbf-669adc2be504" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToParent_019e64ea-07eb-7710-bad7-3c95ac9a3806" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToParent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e64ea-07eb-7bd5-8845-3c7c1a1144ad" xlink:to="loc_us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToParent_019e64ea-07eb-7710-bad7-3c95ac9a3806" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_ReclassificationsDueToBusinessDivestiture_019fcb2e-b520-7f08-8262-b32021682b9f" xlink:href="scor-20260630.xsd#scor_ReclassificationsDueToBusinessDivestiture"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e64ea-07eb-7bd5-8845-3c7c1a1144ad" xlink:to="loc_scor_ReclassificationsDueToBusinessDivestiture_019fcb2e-b520-7f08-8262-b32021682b9f" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesOutstanding_019e64ea-07eb-77d7-8236-4e438742ccad" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockSharesOutstanding"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_019e64ea-07eb-726b-90fe-bb40a68c00e3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockholdersEquity"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.comscore.com/role/SummaryofSignificantAccountingPoliciesNarrativeDetails" xlink:type="simple" xlink:href="scor-20260630.xsd#SummaryofSignificantAccountingPoliciesNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.comscore.com/role/SummaryofSignificantAccountingPoliciesNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsidiarySaleOfStockLineItems_019e64ea-07eb-7a22-869d-7525c7a7385c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsidiarySaleOfStockLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsidiaryOrEquityMethodInvesteeSaleOfStockBySubsidiaryOrEquityInvesteeTable_019e64ea-07eb-7ad1-8e3a-b758a6a3daff" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsidiaryOrEquityMethodInvesteeSaleOfStockBySubsidiaryOrEquityInvesteeTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SubsidiarySaleOfStockLineItems_019e64ea-07eb-7a22-869d-7525c7a7385c" xlink:to="loc_us-gaap_SubsidiaryOrEquityMethodInvesteeSaleOfStockBySubsidiaryOrEquityInvesteeTable_019e64ea-07eb-7ad1-8e3a-b758a6a3daff" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementClassOfStockAxis_019e64ea-07eb-740d-a1b3-2b99da8cc204" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementClassOfStockAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_SubsidiaryOrEquityMethodInvesteeSaleOfStockBySubsidiaryOrEquityInvesteeTable_019e64ea-07eb-7ad1-8e3a-b758a6a3daff" xlink:to="loc_us-gaap_StatementClassOfStockAxis_019e64ea-07eb-740d-a1b3-2b99da8cc204" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_019e64ea-07eb-740d-a1b3-2b99da8cc204_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_019e64ea-07eb-740d-a1b3-2b99da8cc204" xlink:to="loc_us-gaap_ClassOfStockDomain_019e64ea-07eb-740d-a1b3-2b99da8cc204_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_019e64ea-07eb-77f9-b934-652b0b269a2e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_019e64ea-07eb-740d-a1b3-2b99da8cc204" xlink:to="loc_us-gaap_ClassOfStockDomain_019e64ea-07eb-77f9-b934-652b0b269a2e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_SeriesBRedeemableConvertiblePreferredStockMember_019e64ea-07eb-7f35-b21f-85a748eae3d6" xlink:href="scor-20260630.xsd#scor_SeriesBRedeemableConvertiblePreferredStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_019e64ea-07eb-77f9-b934-652b0b269a2e" xlink:to="loc_scor_SeriesBRedeemableConvertiblePreferredStockMember_019e64ea-07eb-7f35-b21f-85a748eae3d6" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_SeriesCRedeemableConvertiblePreferredStockMember_019e64ea-07eb-7f6b-8dfe-9e0700a94244" xlink:href="scor-20260630.xsd#scor_SeriesCRedeemableConvertiblePreferredStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_019e64ea-07eb-77f9-b934-652b0b269a2e" xlink:to="loc_scor_SeriesCRedeemableConvertiblePreferredStockMember_019e64ea-07eb-7f6b-8dfe-9e0700a94244" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LegalEntityAxis_019e64ea-07eb-7d38-893b-d53a741cfb8e" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_LegalEntityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_SubsidiaryOrEquityMethodInvesteeSaleOfStockBySubsidiaryOrEquityInvesteeTable_019e64ea-07eb-7ad1-8e3a-b758a6a3daff" xlink:to="loc_dei_LegalEntityAxis_019e64ea-07eb-7d38-893b-d53a741cfb8e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_019e64ea-07eb-7d38-893b-d53a741cfb8e_default" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_019e64ea-07eb-7d38-893b-d53a741cfb8e" xlink:to="loc_dei_EntityDomain_019e64ea-07eb-7d38-893b-d53a741cfb8e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_019e64ea-07eb-705a-82e1-5fe3a8572c79" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_019e64ea-07eb-7d38-893b-d53a741cfb8e" xlink:to="loc_dei_EntityDomain_019e64ea-07eb-705a-82e1-5fe3a8572c79" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_QurateRetailIncMember_019e64ea-07eb-7950-b1cf-505a73774586" xlink:href="scor-20260630.xsd#scor_QurateRetailIncMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_019e64ea-07eb-705a-82e1-5fe3a8572c79" xlink:to="loc_scor_QurateRetailIncMember_019e64ea-07eb-7950-b1cf-505a73774586" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsidiarySaleOfStockAxis_019e64ea-07eb-7752-a21d-75c5d2d0ecd2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsidiarySaleOfStockAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_SubsidiaryOrEquityMethodInvesteeSaleOfStockBySubsidiaryOrEquityInvesteeTable_019e64ea-07eb-7ad1-8e3a-b758a6a3daff" xlink:to="loc_us-gaap_SubsidiarySaleOfStockAxis_019e64ea-07eb-7752-a21d-75c5d2d0ecd2" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SaleOfStockNameOfTransactionDomain_019e64ea-07eb-7752-a21d-75c5d2d0ecd2_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SaleOfStockNameOfTransactionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_SubsidiarySaleOfStockAxis_019e64ea-07eb-7752-a21d-75c5d2d0ecd2" xlink:to="loc_us-gaap_SaleOfStockNameOfTransactionDomain_019e64ea-07eb-7752-a21d-75c5d2d0ecd2_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SaleOfStockNameOfTransactionDomain_019e64ea-07eb-72c6-ace4-8abba8a41ca2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SaleOfStockNameOfTransactionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_SubsidiarySaleOfStockAxis_019e64ea-07eb-7752-a21d-75c5d2d0ecd2" xlink:to="loc_us-gaap_SaleOfStockNameOfTransactionDomain_019e64ea-07eb-72c6-ace4-8abba8a41ca2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockMember_019e64ea-07eb-7040-9f4e-c697dd58bc77" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PreferredStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SaleOfStockNameOfTransactionDomain_019e64ea-07eb-72c6-ace4-8abba8a41ca2" xlink:to="loc_us-gaap_PreferredStockMember_019e64ea-07eb-7040-9f4e-c697dd58bc77" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CounterpartyNameAxis_019e64ea-07eb-7bbe-a38f-ed8f5b066a5c" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_CounterpartyNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_SubsidiaryOrEquityMethodInvesteeSaleOfStockBySubsidiaryOrEquityInvesteeTable_019e64ea-07eb-7ad1-8e3a-b758a6a3daff" xlink:to="loc_srt_CounterpartyNameAxis_019e64ea-07eb-7bbe-a38f-ed8f5b066a5c" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_019e64ea-07eb-7bbe-a38f-ed8f5b066a5c_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CounterpartyNameAxis_019e64ea-07eb-7bbe-a38f-ed8f5b066a5c" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_019e64ea-07eb-7bbe-a38f-ed8f5b066a5c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_019e64ea-07eb-7b8b-a427-630cbaea5b23" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CounterpartyNameAxis_019e64ea-07eb-7bbe-a38f-ed8f5b066a5c" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_019e64ea-07eb-7b8b-a427-630cbaea5b23" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_LibertyMember_019e64ea-07eb-796e-be59-b06548b38d95" xlink:href="scor-20260630.xsd#scor_LibertyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_019e64ea-07eb-7b8b-a427-630cbaea5b23" xlink:to="loc_scor_LibertyMember_019e64ea-07eb-796e-be59-b06548b38d95" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_019e64ea-07eb-7f5d-89c0-c6e6d830575d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_SubsidiaryOrEquityMethodInvesteeSaleOfStockBySubsidiaryOrEquityInvesteeTable_019e64ea-07eb-7ad1-8e3a-b758a6a3daff" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_019e64ea-07eb-7f5d-89c0-c6e6d830575d" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_019e64ea-07eb-7f5d-89c0-c6e6d830575d_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_019e64ea-07eb-7f5d-89c0-c6e6d830575d" xlink:to="loc_us-gaap_EquityComponentDomain_019e64ea-07eb-7f5d-89c0-c6e6d830575d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_019e64ea-07eb-7997-918c-4a672034d0ce" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_019e64ea-07eb-7f5d-89c0-c6e6d830575d" xlink:to="loc_us-gaap_EquityComponentDomain_019e64ea-07eb-7997-918c-4a672034d0ce" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockMember_019e64ea-07eb-7579-92b9-a4f390dc1e73" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_019e64ea-07eb-7997-918c-4a672034d0ce" xlink:to="loc_us-gaap_CommonStockMember_019e64ea-07eb-7579-92b9-a4f390dc1e73" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TemporaryEquityParOrStatedValuePerShare_019e64ea-07eb-7ff0-ad3f-b30cbc3136d4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TemporaryEquityParOrStatedValuePerShare"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsidiarySaleOfStockLineItems_019e64ea-07eb-7a22-869d-7525c7a7385c" xlink:to="loc_us-gaap_TemporaryEquityParOrStatedValuePerShare_019e64ea-07eb-7ff0-ad3f-b30cbc3136d4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SaleOfStockNumberOfSharesIssuedInTransaction_019e64ea-07eb-7e72-8d95-801bdc9fe29f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SaleOfStockNumberOfSharesIssuedInTransaction"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsidiarySaleOfStockLineItems_019e64ea-07eb-7a22-869d-7525c7a7385c" xlink:to="loc_us-gaap_SaleOfStockNumberOfSharesIssuedInTransaction_019e64ea-07eb-7e72-8d95-801bdc9fe29f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_TemporaryEquityStockIssuedDuringPeriodSharesNewIssues_019e64ea-07eb-772e-a13e-69a2eea87bb1" xlink:href="scor-20260630.xsd#scor_TemporaryEquityStockIssuedDuringPeriodSharesNewIssues"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsidiarySaleOfStockLineItems_019e64ea-07eb-7a22-869d-7525c7a7385c" xlink:to="loc_scor_TemporaryEquityStockIssuedDuringPeriodSharesNewIssues_019e64ea-07eb-772e-a13e-69a2eea87bb1" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DividendsPayableCurrentAndNoncurrent_019e64ea-07eb-7d48-aac3-2d8e9461fc02" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DividendsPayableCurrentAndNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsidiarySaleOfStockLineItems_019e64ea-07eb-7a22-869d-7525c7a7385c" xlink:to="loc_us-gaap_DividendsPayableCurrentAndNoncurrent_019e64ea-07eb-7d48-aac3-2d8e9461fc02" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_PreferredStockSpecialDividendThreshold_019e64ea-07eb-745f-bb9c-fca27e7da93a" xlink:href="scor-20260630.xsd#scor_PreferredStockSpecialDividendThreshold"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsidiarySaleOfStockLineItems_019e64ea-07eb-7a22-869d-7525c7a7385c" xlink:to="loc_scor_PreferredStockSpecialDividendThreshold_019e64ea-07eb-745f-bb9c-fca27e7da93a" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockLiquidationPreferenceValue_019e64ea-07eb-7dad-99c8-4bcd6ae22ddd" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PreferredStockLiquidationPreferenceValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsidiarySaleOfStockLineItems_019e64ea-07eb-7a22-869d-7525c7a7385c" xlink:to="loc_us-gaap_PreferredStockLiquidationPreferenceValue_019e64ea-07eb-7dad-99c8-4bcd6ae22ddd" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_StockExchangeAgreementSharesExchanged_019e64ea-07eb-7f84-80a1-3a295deba0f4" xlink:href="scor-20260630.xsd#scor_StockExchangeAgreementSharesExchanged"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsidiarySaleOfStockLineItems_019e64ea-07eb-7a22-869d-7525c7a7385c" xlink:to="loc_scor_StockExchangeAgreementSharesExchanged_019e64ea-07eb-7f84-80a1-3a295deba0f4" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_StockExchangeAgreementNewStockReceived_019e64ea-07eb-7a6a-aa8c-bc9ee7741b25" xlink:href="scor-20260630.xsd#scor_StockExchangeAgreementNewStockReceived"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsidiarySaleOfStockLineItems_019e64ea-07eb-7a22-869d-7525c7a7385c" xlink:to="loc_scor_StockExchangeAgreementNewStockReceived_019e64ea-07eb-7a6a-aa8c-bc9ee7741b25" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockParOrStatedValuePerShare_019e64ea-07eb-73c8-9edf-3ba2fd11c86e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockParOrStatedValuePerShare"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsidiarySaleOfStockLineItems_019e64ea-07eb-7a22-869d-7525c7a7385c" xlink:to="loc_us-gaap_CommonStockParOrStatedValuePerShare_019e64ea-07eb-73c8-9edf-3ba2fd11c86e" xlink:type="arc" order="8"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.comscore.com/role/SummaryofSignificantAccountingPoliciesScheduleofCommonStockEquivalentsforSecuritiesOutstandingExcludedfromComputationofDilutedNetLossperShareDetails" xlink:type="simple" xlink:href="scor-20260630.xsd#SummaryofSignificantAccountingPoliciesScheduleofCommonStockEquivalentsforSecuritiesOutstandingExcludedfromComputationofDilutedNetLossperShareDetails"/>
  <link:definitionLink xlink:role="http://www.comscore.com/role/SummaryofSignificantAccountingPoliciesScheduleofCommonStockEquivalentsforSecuritiesOutstandingExcludedfromComputationofDilutedNetLossperShareDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_019e64ea-07eb-7ff6-9733-285458f68be8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable_019e64ea-07eb-78d0-bd0d-79e1e18fc028" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_019e64ea-07eb-7ff6-9733-285458f68be8" xlink:to="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable_019e64ea-07eb-78d0-bd0d-79e1e18fc028" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementClassOfStockAxis_019e64ea-07eb-7b34-9dbb-9ca144625831" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementClassOfStockAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable_019e64ea-07eb-78d0-bd0d-79e1e18fc028" xlink:to="loc_us-gaap_StatementClassOfStockAxis_019e64ea-07eb-7b34-9dbb-9ca144625831" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_019e64ea-07eb-7b34-9dbb-9ca144625831_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_019e64ea-07eb-7b34-9dbb-9ca144625831" xlink:to="loc_us-gaap_ClassOfStockDomain_019e64ea-07eb-7b34-9dbb-9ca144625831_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_019e64ea-07eb-7030-a307-d9aecd8f7c8b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_019e64ea-07eb-7b34-9dbb-9ca144625831" xlink:to="loc_us-gaap_ClassOfStockDomain_019e64ea-07eb-7030-a307-d9aecd8f7c8b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_SeriesCRedeemableConvertiblePreferredStockMember_019e64ea-07eb-7180-8841-19d69e40ae70" xlink:href="scor-20260630.xsd#scor_SeriesCRedeemableConvertiblePreferredStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_019e64ea-07eb-7030-a307-d9aecd8f7c8b" xlink:to="loc_scor_SeriesCRedeemableConvertiblePreferredStockMember_019e64ea-07eb-7180-8841-19d69e40ae70" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_SeriesBRedeemableConvertiblePreferredStockMember_019e64ea-07eb-75b4-ab0b-6e5a4ce558ca" xlink:href="scor-20260630.xsd#scor_SeriesBRedeemableConvertiblePreferredStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_019e64ea-07eb-7030-a307-d9aecd8f7c8b" xlink:to="loc_scor_SeriesBRedeemableConvertiblePreferredStockMember_019e64ea-07eb-75b4-ab0b-6e5a4ce558ca" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_019e64ea-07eb-7959-aba6-610e34a3647a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable_019e64ea-07eb-78d0-bd0d-79e1e18fc028" xlink:to="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_019e64ea-07eb-7959-aba6-610e34a3647a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesNameDomain_019e64ea-07eb-7959-aba6-610e34a3647a_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AntidilutiveSecuritiesNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_019e64ea-07eb-7959-aba6-610e34a3647a" xlink:to="loc_us-gaap_AntidilutiveSecuritiesNameDomain_019e64ea-07eb-7959-aba6-610e34a3647a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesNameDomain_019e64ea-07eb-703e-8e42-8772be83c8b9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AntidilutiveSecuritiesNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_019e64ea-07eb-7959-aba6-610e34a3647a" xlink:to="loc_us-gaap_AntidilutiveSecuritiesNameDomain_019e64ea-07eb-703e-8e42-8772be83c8b9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RedeemableConvertiblePreferredStockMember_019e64ea-07eb-77aa-8c4e-3731bb31ee58" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RedeemableConvertiblePreferredStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesNameDomain_019e64ea-07eb-703e-8e42-8772be83c8b9" xlink:to="loc_us-gaap_RedeemableConvertiblePreferredStockMember_019e64ea-07eb-77aa-8c4e-3731bb31ee58" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_StockOptionsRestrictedStockUnitsMember_019e64ea-07eb-7097-b993-a8797c5cdfb0" xlink:href="scor-20260630.xsd#scor_StockOptionsRestrictedStockUnitsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesNameDomain_019e64ea-07eb-703e-8e42-8772be83c8b9" xlink:to="loc_scor_StockOptionsRestrictedStockUnitsMember_019e64ea-07eb-7097-b993-a8797c5cdfb0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_019e64ea-07eb-7f69-be24-c641ae454ca3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_019e64ea-07eb-7ff6-9733-285458f68be8" xlink:to="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_019e64ea-07eb-7f69-be24-c641ae454ca3" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.comscore.com/role/DivestitureofMoviesBusinessNarrativeDetails" xlink:type="simple" xlink:href="scor-20260630.xsd#DivestitureofMoviesBusinessNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.comscore.com/role/DivestitureofMoviesBusinessNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_019f039b-be67-7200-b2ec-a635d05a732b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable_019f039b-be67-71a1-a9ee-ed33556a240f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_019f039b-be67-7200-b2ec-a635d05a732b" xlink:to="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable_019f039b-be67-71a1-a9ee-ed33556a240f" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupClassificationAxis_019f039b-be67-7755-bed1-c9401b4e4d97" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DisposalGroupClassificationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable_019f039b-be67-71a1-a9ee-ed33556a240f" xlink:to="loc_us-gaap_DisposalGroupClassificationAxis_019f039b-be67-7755-bed1-c9401b4e4d97" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupClassificationDomain_019f039b-be67-7755-bed1-c9401b4e4d97_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DisposalGroupClassificationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DisposalGroupClassificationAxis_019f039b-be67-7755-bed1-c9401b4e4d97" xlink:to="loc_us-gaap_DisposalGroupClassificationDomain_019f039b-be67-7755-bed1-c9401b4e4d97_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupClassificationDomain_019f039b-be67-7789-96b8-d9f711007822" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DisposalGroupClassificationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DisposalGroupClassificationAxis_019f039b-be67-7755-bed1-c9401b4e4d97" xlink:to="loc_us-gaap_DisposalGroupClassificationDomain_019f039b-be67-7789-96b8-d9f711007822" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupDisposedOfBySaleNotDiscontinuedOperationsMember_019f039c-067b-78f8-b3ad-90098afe8a37" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DisposalGroupDisposedOfBySaleNotDiscontinuedOperationsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisposalGroupClassificationDomain_019f039b-be67-7789-96b8-d9f711007822" xlink:to="loc_us-gaap_DisposalGroupDisposedOfBySaleNotDiscontinuedOperationsMember_019f039c-067b-78f8-b3ad-90098afe8a37" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_019f039c-0c74-7638-bb5b-fd44fb3e7220" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable_019f039b-be67-71a1-a9ee-ed33556a240f" xlink:to="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_019f039c-0c74-7638-bb5b-fd44fb3e7220" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_019f039c-0c74-7638-bb5b-fd44fb3e7220_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_019f039c-0c74-7638-bb5b-fd44fb3e7220" xlink:to="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_019f039c-0c74-7638-bb5b-fd44fb3e7220_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_019f039c-0c74-798f-8921-86cd4390e0af" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_019f039c-0c74-7638-bb5b-fd44fb3e7220" xlink:to="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_019f039c-0c74-798f-8921-86cd4390e0af" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_MoviesBusinessMember_019f039c-16ec-7f9d-ab4f-a5e7c7a51012" xlink:href="scor-20260630.xsd#scor_MoviesBusinessMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_019f039c-0c74-798f-8921-86cd4390e0af" xlink:to="loc_scor_MoviesBusinessMember_019f039c-16ec-7f9d-ab4f-a5e7c7a51012" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementOfFinancialPositionLocationBalanceAxis_019fc85b-64ac-784f-82c8-bacead5ae3df" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementOfFinancialPositionLocationBalanceAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable_019f039b-be67-71a1-a9ee-ed33556a240f" xlink:to="loc_us-gaap_StatementOfFinancialPositionLocationBalanceAxis_019fc85b-64ac-784f-82c8-bacead5ae3df" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_DisposalGroupIncludingDiscontinuedOperationOwnershipPercentageInDisposedAsset_019ff461-de02-7108-8d10-0b9df569af46" xlink:href="scor-20260630.xsd#scor_DisposalGroupIncludingDiscontinuedOperationOwnershipPercentageInDisposedAsset"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_019f039b-be67-7200-b2ec-a635d05a732b" xlink:to="loc_scor_DisposalGroupIncludingDiscontinuedOperationOwnershipPercentageInDisposedAsset_019ff461-de02-7108-8d10-0b9df569af46" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationConsideration_019ff461-de02-7ac2-8e75-7225bc626c77" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DisposalGroupIncludingDiscontinuedOperationConsideration"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_019f039b-be67-7200-b2ec-a635d05a732b" xlink:to="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationConsideration_019ff461-de02-7ac2-8e75-7225bc626c77" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_DisposalGroupIncludingDiscontinuedOperationEstimatedPostClosingAdjustments_019feb52-9a8f-75f0-80bd-c91e9e5d6165" xlink:href="scor-20260630.xsd#scor_DisposalGroupIncludingDiscontinuedOperationEstimatedPostClosingAdjustments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_019f039b-be67-7200-b2ec-a635d05a732b" xlink:to="loc_scor_DisposalGroupIncludingDiscontinuedOperationEstimatedPostClosingAdjustments_019feb52-9a8f-75f0-80bd-c91e9e5d6165" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromDivestitureOfBusinesses_019ee111-152b-7014-a175-34522f637b13" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProceedsFromDivestitureOfBusinesses"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_019f039b-be67-7200-b2ec-a635d05a732b" xlink:to="loc_us-gaap_ProceedsFromDivestitureOfBusinesses_019ee111-152b-7014-a175-34522f637b13" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_DisposalGroupIncludingDiscontinuedOperationCustomaryAdjustments_019ff44b-2ebd-7d61-bc19-3f0d9c604a56" xlink:href="scor-20260630.xsd#scor_DisposalGroupIncludingDiscontinuedOperationCustomaryAdjustments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_019f039b-be67-7200-b2ec-a635d05a732b" xlink:to="loc_scor_DisposalGroupIncludingDiscontinuedOperationCustomaryAdjustments_019ff44b-2ebd-7d61-bc19-3f0d9c604a56" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_DisposalGroupIncludingDiscontinuedOperationHeldInEscrow_019f039c-d313-7a93-9b24-58f1a905c83f" xlink:href="scor-20260630.xsd#scor_DisposalGroupIncludingDiscontinuedOperationHeldInEscrow"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_019f039b-be67-7200-b2ec-a635d05a732b" xlink:to="loc_scor_DisposalGroupIncludingDiscontinuedOperationHeldInEscrow_019f039c-d313-7a93-9b24-58f1a905c83f" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainLossOnSaleOfBusiness_019f2263-1785-760c-884e-fafc77e73808" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_GainLossOnSaleOfBusiness"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_019f039b-be67-7200-b2ec-a635d05a732b" xlink:to="loc_us-gaap_GainLossOnSaleOfBusiness_019f2263-1785-760c-884e-fafc77e73808" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_DisposalGroupIncludingDiscontinuedOperationDirectCostsToSell_019fc54b-61ce-7ba6-963a-b327f1d9a129" xlink:href="scor-20260630.xsd#scor_DisposalGroupIncludingDiscontinuedOperationDirectCostsToSell"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_019f039b-be67-7200-b2ec-a635d05a732b" xlink:to="loc_scor_DisposalGroupIncludingDiscontinuedOperationDirectCostsToSell_019fc54b-61ce-7ba6-963a-b327f1d9a129" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillImpairmentLoss_019fb33c-8cce-716c-b6f7-fb8d57ef847a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_GoodwillImpairmentLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_019f039b-be67-7200-b2ec-a635d05a732b" xlink:to="loc_us-gaap_GoodwillImpairmentLoss_019fb33c-8cce-716c-b6f7-fb8d57ef847a" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationOtherIncome_019fe980-1426-7d02-b51a-2366f2223340" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DisposalGroupIncludingDiscontinuedOperationOtherIncome"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_019f039b-be67-7200-b2ec-a635d05a732b" xlink:to="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationOtherIncome_019fe980-1426-7d02-b51a-2366f2223340" xlink:type="arc" order="9"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.comscore.com/role/DivestitureofMoviesBusinessNarrativeDetails_1" xlink:type="simple" xlink:href="scor-20260630.xsd#DivestitureofMoviesBusinessNarrativeDetails_1"/>
  <link:definitionLink xlink:role="http://www.comscore.com/role/DivestitureofMoviesBusinessNarrativeDetails_1" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_019f039b-be67-7200-b2ec-a635d05a732b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable_019f039b-be67-71a1-a9ee-ed33556a240f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_019f039b-be67-7200-b2ec-a635d05a732b" xlink:to="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable_019f039b-be67-71a1-a9ee-ed33556a240f" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupClassificationAxis_019f039b-be67-7755-bed1-c9401b4e4d97" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DisposalGroupClassificationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable_019f039b-be67-71a1-a9ee-ed33556a240f" xlink:to="loc_us-gaap_DisposalGroupClassificationAxis_019f039b-be67-7755-bed1-c9401b4e4d97" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupClassificationDomain_019f039b-be67-7755-bed1-c9401b4e4d97_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DisposalGroupClassificationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DisposalGroupClassificationAxis_019f039b-be67-7755-bed1-c9401b4e4d97" xlink:to="loc_us-gaap_DisposalGroupClassificationDomain_019f039b-be67-7755-bed1-c9401b4e4d97_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupClassificationDomain_019f039b-be67-7789-96b8-d9f711007822" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DisposalGroupClassificationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DisposalGroupClassificationAxis_019f039b-be67-7755-bed1-c9401b4e4d97" xlink:to="loc_us-gaap_DisposalGroupClassificationDomain_019f039b-be67-7789-96b8-d9f711007822" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupDisposedOfBySaleNotDiscontinuedOperationsMember_019f039c-067b-78f8-b3ad-90098afe8a37" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DisposalGroupDisposedOfBySaleNotDiscontinuedOperationsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisposalGroupClassificationDomain_019f039b-be67-7789-96b8-d9f711007822" xlink:to="loc_us-gaap_DisposalGroupDisposedOfBySaleNotDiscontinuedOperationsMember_019f039c-067b-78f8-b3ad-90098afe8a37" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_019f039c-0c74-7638-bb5b-fd44fb3e7220" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable_019f039b-be67-71a1-a9ee-ed33556a240f" xlink:to="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_019f039c-0c74-7638-bb5b-fd44fb3e7220" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_019f039c-0c74-7638-bb5b-fd44fb3e7220_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_019f039c-0c74-7638-bb5b-fd44fb3e7220" xlink:to="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_019f039c-0c74-7638-bb5b-fd44fb3e7220_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_019f039c-0c74-798f-8921-86cd4390e0af" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_019f039c-0c74-7638-bb5b-fd44fb3e7220" xlink:to="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_019f039c-0c74-798f-8921-86cd4390e0af" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_MoviesBusinessMember_019f039c-16ec-7f9d-ab4f-a5e7c7a51012" xlink:href="scor-20260630.xsd#scor_MoviesBusinessMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_019f039c-0c74-798f-8921-86cd4390e0af" xlink:to="loc_scor_MoviesBusinessMember_019f039c-16ec-7f9d-ab4f-a5e7c7a51012" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_DisposalGroupIncludingDiscontinuedOperationOwnershipPercentageInDisposedAsset_019ff461-de02-7108-8d10-0b9df569af46" xlink:href="scor-20260630.xsd#scor_DisposalGroupIncludingDiscontinuedOperationOwnershipPercentageInDisposedAsset"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_019f039b-be67-7200-b2ec-a635d05a732b" xlink:to="loc_scor_DisposalGroupIncludingDiscontinuedOperationOwnershipPercentageInDisposedAsset_019ff461-de02-7108-8d10-0b9df569af46" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationConsideration_019ff461-de02-7ac2-8e75-7225bc626c77" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DisposalGroupIncludingDiscontinuedOperationConsideration"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_019f039b-be67-7200-b2ec-a635d05a732b" xlink:to="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationConsideration_019ff461-de02-7ac2-8e75-7225bc626c77" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_DisposalGroupIncludingDiscontinuedOperationEstimatedPostClosingAdjustments_019feb52-9a8f-75f0-80bd-c91e9e5d6165" xlink:href="scor-20260630.xsd#scor_DisposalGroupIncludingDiscontinuedOperationEstimatedPostClosingAdjustments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_019f039b-be67-7200-b2ec-a635d05a732b" xlink:to="loc_scor_DisposalGroupIncludingDiscontinuedOperationEstimatedPostClosingAdjustments_019feb52-9a8f-75f0-80bd-c91e9e5d6165" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromDivestitureOfBusinesses_019ee111-152b-7014-a175-34522f637b13" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProceedsFromDivestitureOfBusinesses"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_019f039b-be67-7200-b2ec-a635d05a732b" xlink:to="loc_us-gaap_ProceedsFromDivestitureOfBusinesses_019ee111-152b-7014-a175-34522f637b13" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_DisposalGroupIncludingDiscontinuedOperationCustomaryAdjustments_019ff44b-2ebd-7d61-bc19-3f0d9c604a56" xlink:href="scor-20260630.xsd#scor_DisposalGroupIncludingDiscontinuedOperationCustomaryAdjustments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_019f039b-be67-7200-b2ec-a635d05a732b" xlink:to="loc_scor_DisposalGroupIncludingDiscontinuedOperationCustomaryAdjustments_019ff44b-2ebd-7d61-bc19-3f0d9c604a56" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_DisposalGroupIncludingDiscontinuedOperationHeldInEscrow_019f039c-d313-7a93-9b24-58f1a905c83f" xlink:href="scor-20260630.xsd#scor_DisposalGroupIncludingDiscontinuedOperationHeldInEscrow"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_019f039b-be67-7200-b2ec-a635d05a732b" xlink:to="loc_scor_DisposalGroupIncludingDiscontinuedOperationHeldInEscrow_019f039c-d313-7a93-9b24-58f1a905c83f" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainLossOnSaleOfBusiness_019f2263-1785-760c-884e-fafc77e73808" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_GainLossOnSaleOfBusiness"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_019f039b-be67-7200-b2ec-a635d05a732b" xlink:to="loc_us-gaap_GainLossOnSaleOfBusiness_019f2263-1785-760c-884e-fafc77e73808" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_DisposalGroupIncludingDiscontinuedOperationDirectCostsToSell_019fc54b-61ce-7ba6-963a-b327f1d9a129" xlink:href="scor-20260630.xsd#scor_DisposalGroupIncludingDiscontinuedOperationDirectCostsToSell"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_019f039b-be67-7200-b2ec-a635d05a732b" xlink:to="loc_scor_DisposalGroupIncludingDiscontinuedOperationDirectCostsToSell_019fc54b-61ce-7ba6-963a-b327f1d9a129" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillImpairmentLoss_019fb33c-8cce-716c-b6f7-fb8d57ef847a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_GoodwillImpairmentLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_019f039b-be67-7200-b2ec-a635d05a732b" xlink:to="loc_us-gaap_GoodwillImpairmentLoss_019fb33c-8cce-716c-b6f7-fb8d57ef847a" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationOtherIncome_019fe980-1426-7d02-b51a-2366f2223340" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DisposalGroupIncludingDiscontinuedOperationOtherIncome"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_019f039b-be67-7200-b2ec-a635d05a732b" xlink:to="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationOtherIncome_019fe980-1426-7d02-b51a-2366f2223340" xlink:type="arc" order="9"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.comscore.com/role/DivestitureofMoviesBusinessScheduleofLossDetails" xlink:type="simple" xlink:href="scor-20260630.xsd#DivestitureofMoviesBusinessScheduleofLossDetails"/>
  <link:definitionLink xlink:role="http://www.comscore.com/role/DivestitureofMoviesBusinessScheduleofLossDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_019f4a98-d0f0-7996-87f8-19cbc9943b18" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable_019f4a98-d0f0-73e1-b659-70c31fbe0cd7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_019f4a98-d0f0-7996-87f8-19cbc9943b18" xlink:to="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable_019f4a98-d0f0-73e1-b659-70c31fbe0cd7" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupClassificationAxis_019f4a98-d0f0-7469-8ad9-631c6339b09d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DisposalGroupClassificationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable_019f4a98-d0f0-73e1-b659-70c31fbe0cd7" xlink:to="loc_us-gaap_DisposalGroupClassificationAxis_019f4a98-d0f0-7469-8ad9-631c6339b09d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupClassificationDomain_019f4a98-d0f0-7469-8ad9-631c6339b09d_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DisposalGroupClassificationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DisposalGroupClassificationAxis_019f4a98-d0f0-7469-8ad9-631c6339b09d" xlink:to="loc_us-gaap_DisposalGroupClassificationDomain_019f4a98-d0f0-7469-8ad9-631c6339b09d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupClassificationDomain_019f4a98-d0f0-769b-9b53-c81ac1885e3a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DisposalGroupClassificationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DisposalGroupClassificationAxis_019f4a98-d0f0-7469-8ad9-631c6339b09d" xlink:to="loc_us-gaap_DisposalGroupClassificationDomain_019f4a98-d0f0-769b-9b53-c81ac1885e3a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupDisposedOfBySaleNotDiscontinuedOperationsMember_019f4a98-d0f0-73bd-9f58-65363188eff8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DisposalGroupDisposedOfBySaleNotDiscontinuedOperationsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisposalGroupClassificationDomain_019f4a98-d0f0-769b-9b53-c81ac1885e3a" xlink:to="loc_us-gaap_DisposalGroupDisposedOfBySaleNotDiscontinuedOperationsMember_019f4a98-d0f0-73bd-9f58-65363188eff8" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_019f4a98-d0f0-726c-b667-8830168d05a2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable_019f4a98-d0f0-73e1-b659-70c31fbe0cd7" xlink:to="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_019f4a98-d0f0-726c-b667-8830168d05a2" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_019f4a98-d0f0-726c-b667-8830168d05a2_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_019f4a98-d0f0-726c-b667-8830168d05a2" xlink:to="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_019f4a98-d0f0-726c-b667-8830168d05a2_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_019f4a98-d0f0-702f-b557-65c603955d74" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_019f4a98-d0f0-726c-b667-8830168d05a2" xlink:to="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_019f4a98-d0f0-702f-b557-65c603955d74" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_MoviesBusinessMember_019f4a98-d0f0-79ad-8190-c7873a58237b" xlink:href="scor-20260630.xsd#scor_MoviesBusinessMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_019f4a98-d0f0-702f-b557-65c603955d74" xlink:to="loc_scor_MoviesBusinessMember_019f4a98-d0f0-79ad-8190-c7873a58237b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_DisposalGroupIncludingDiscontinuedOperationPurchasePriceConsideration_019f4a98-d0f0-74b9-ba9c-7c91b4a9f07c" xlink:href="scor-20260630.xsd#scor_DisposalGroupIncludingDiscontinuedOperationPurchasePriceConsideration"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_019f4a98-d0f0-7996-87f8-19cbc9943b18" xlink:to="loc_scor_DisposalGroupIncludingDiscontinuedOperationPurchasePriceConsideration_019f4a98-d0f0-74b9-ba9c-7c91b4a9f07c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_DisposalGroupIncludingDiscontinuedOperationNetAssetsDivested_019fb2e6-ba65-7a02-9680-a311427bf6bb" xlink:href="scor-20260630.xsd#scor_DisposalGroupIncludingDiscontinuedOperationNetAssetsDivested"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_019f4a98-d0f0-7996-87f8-19cbc9943b18" xlink:to="loc_scor_DisposalGroupIncludingDiscontinuedOperationNetAssetsDivested_019fb2e6-ba65-7a02-9680-a311427bf6bb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_DisposalGroupIncludingDiscontinuedOperationAccumulatedOtherComprehensiveIncomeLoss_019f4a98-d0f0-71a2-91f1-10d6c281db41" xlink:href="scor-20260630.xsd#scor_DisposalGroupIncludingDiscontinuedOperationAccumulatedOtherComprehensiveIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_019f4a98-d0f0-7996-87f8-19cbc9943b18" xlink:to="loc_scor_DisposalGroupIncludingDiscontinuedOperationAccumulatedOtherComprehensiveIncomeLoss_019f4a98-d0f0-71a2-91f1-10d6c281db41" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_GainLossOnDispositionOfBusinessGross_019fb2de-7c04-71e6-b28f-3d9088093d47" xlink:href="scor-20260630.xsd#scor_GainLossOnDispositionOfBusinessGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_019f4a98-d0f0-7996-87f8-19cbc9943b18" xlink:to="loc_scor_GainLossOnDispositionOfBusinessGross_019fb2de-7c04-71e6-b28f-3d9088093d47" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_DisposalGroupIncludingDiscontinuedOperationDirectCostsToSell_019feb58-800b-79a0-93f6-23481acc43bb" xlink:href="scor-20260630.xsd#scor_DisposalGroupIncludingDiscontinuedOperationDirectCostsToSell"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_019f4a98-d0f0-7996-87f8-19cbc9943b18" xlink:to="loc_scor_DisposalGroupIncludingDiscontinuedOperationDirectCostsToSell_019feb58-800b-79a0-93f6-23481acc43bb" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainLossOnSaleOfBusiness_019f4a98-d0f0-7512-8b32-f01e5b916ac6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_GainLossOnSaleOfBusiness"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_019f4a98-d0f0-7996-87f8-19cbc9943b18" xlink:to="loc_us-gaap_GainLossOnSaleOfBusiness_019f4a98-d0f0-7512-8b32-f01e5b916ac6" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationGoodwill1_019fb338-87f5-70cf-bb1e-9f4b35bd1305" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DisposalGroupIncludingDiscontinuedOperationGoodwill1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_019f4a98-d0f0-7996-87f8-19cbc9943b18" xlink:to="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationGoodwill1_019fb338-87f5-70cf-bb1e-9f4b35bd1305" xlink:type="arc" order="6"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.comscore.com/role/RevenueRecognitionScheduleofDisaggregationofRevenueDetails" xlink:type="simple" xlink:href="scor-20260630.xsd#RevenueRecognitionScheduleofDisaggregationofRevenueDetails"/>
  <link:definitionLink xlink:role="http://www.comscore.com/role/RevenueRecognitionScheduleofDisaggregationofRevenueDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisaggregationOfRevenueLineItems_019e64ea-07eb-7995-ab2d-172ca66b0e4d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DisaggregationOfRevenueLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisaggregationOfRevenueTable_019e64ea-07eb-7b3b-b3c8-504ca0d5d408" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DisaggregationOfRevenueTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_019e64ea-07eb-7995-ab2d-172ca66b0e4d" xlink:to="loc_us-gaap_DisaggregationOfRevenueTable_019e64ea-07eb-7b3b-b3c8-504ca0d5d408" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_019e64ea-07eb-757d-96b3-18a6a3e8cd5b" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ProductOrServiceAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_019e64ea-07eb-7b3b-b3c8-504ca0d5d408" xlink:to="loc_srt_ProductOrServiceAxis_019e64ea-07eb-757d-96b3-18a6a3e8cd5b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_019e64ea-07eb-757d-96b3-18a6a3e8cd5b_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_019e64ea-07eb-757d-96b3-18a6a3e8cd5b" xlink:to="loc_srt_ProductsAndServicesDomain_019e64ea-07eb-757d-96b3-18a6a3e8cd5b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_019e64ea-07eb-7175-b256-7685dd5aeed5" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_019e64ea-07eb-757d-96b3-18a6a3e8cd5b" xlink:to="loc_srt_ProductsAndServicesDomain_019e64ea-07eb-7175-b256-7685dd5aeed5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_ContentAdMeasurementMember_019e64ea-07eb-7009-9c93-ac413b792b32" xlink:href="scor-20260630.xsd#scor_ContentAdMeasurementMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_019e64ea-07eb-7175-b256-7685dd5aeed5" xlink:to="loc_scor_ContentAdMeasurementMember_019e64ea-07eb-7009-9c93-ac413b792b32" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_ContentAndAdMeasurementSyndicatedAudienceMember_019e64ea-07eb-75fb-92a2-d7b4e914b149" xlink:href="scor-20260630.xsd#scor_ContentAndAdMeasurementSyndicatedAudienceMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_scor_ContentAdMeasurementMember_019e64ea-07eb-7009-9c93-ac413b792b32" xlink:to="loc_scor_ContentAndAdMeasurementSyndicatedAudienceMember_019e64ea-07eb-75fb-92a2-d7b4e914b149" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_ContentAndAdMeasurementCrossPlatformSolutionsMember_019e64ea-07eb-7d30-8b77-27c986e66d8e" xlink:href="scor-20260630.xsd#scor_ContentAndAdMeasurementCrossPlatformSolutionsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_scor_ContentAdMeasurementMember_019e64ea-07eb-7009-9c93-ac413b792b32" xlink:to="loc_scor_ContentAndAdMeasurementCrossPlatformSolutionsMember_019e64ea-07eb-7d30-8b77-27c986e66d8e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_ResearchInsightSolutionsMember_019e64ea-07eb-78eb-ba44-ef49e19e6bd8" xlink:href="scor-20260630.xsd#scor_ResearchInsightSolutionsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_019e64ea-07eb-7175-b256-7685dd5aeed5" xlink:to="loc_scor_ResearchInsightSolutionsMember_019e64ea-07eb-78eb-ba44-ef49e19e6bd8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_StatementGeographicalAxis_019e64ea-07eb-7561-a291-5f28484a7756" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_StatementGeographicalAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_019e64ea-07eb-7b3b-b3c8-504ca0d5d408" xlink:to="loc_srt_StatementGeographicalAxis_019e64ea-07eb-7561-a291-5f28484a7756" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_019e64ea-07eb-7561-a291-5f28484a7756_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_SegmentGeographicalDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_StatementGeographicalAxis_019e64ea-07eb-7561-a291-5f28484a7756" xlink:to="loc_srt_SegmentGeographicalDomain_019e64ea-07eb-7561-a291-5f28484a7756_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_019e64ea-07eb-7f57-b5b8-8196ee4a64b6" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_SegmentGeographicalDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_StatementGeographicalAxis_019e64ea-07eb-7561-a291-5f28484a7756" xlink:to="loc_srt_SegmentGeographicalDomain_019e64ea-07eb-7f57-b5b8-8196ee4a64b6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_country_US_019e64ea-07eb-7d81-b502-200d40ef3aa2" xlink:href="https://xbrl.sec.gov/country/2026/country-2026.xsd#country_US"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_019e64ea-07eb-7f57-b5b8-8196ee4a64b6" xlink:to="loc_country_US_019e64ea-07eb-7d81-b502-200d40ef3aa2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_EuropeMember_019e64ea-07eb-79ce-bf36-f85a36208efe" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_EuropeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_019e64ea-07eb-7f57-b5b8-8196ee4a64b6" xlink:to="loc_srt_EuropeMember_019e64ea-07eb-79ce-bf36-f85a36208efe" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_LatinAmericaMember_019e64ea-07eb-70ba-b34f-f7713fbe6c74" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_LatinAmericaMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_019e64ea-07eb-7f57-b5b8-8196ee4a64b6" xlink:to="loc_srt_LatinAmericaMember_019e64ea-07eb-70ba-b34f-f7713fbe6c74" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_country_CA_019e64ea-07eb-7a56-a4a4-37c8d78fedc7" xlink:href="https://xbrl.sec.gov/country/2026/country-2026.xsd#country_CA"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_019e64ea-07eb-7f57-b5b8-8196ee4a64b6" xlink:to="loc_country_CA_019e64ea-07eb-7a56-a4a4-37c8d78fedc7" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_OtherCountryMember_019e64ea-07eb-796d-a10d-8a46c3e04cf9" xlink:href="scor-20260630.xsd#scor_OtherCountryMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_019e64ea-07eb-7f57-b5b8-8196ee4a64b6" xlink:to="loc_scor_OtherCountryMember_019e64ea-07eb-796d-a10d-8a46c3e04cf9" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TimingOfTransferOfGoodOrServiceAxis_019e64ea-07eb-7f51-98ec-c2fd22ae8cfb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TimingOfTransferOfGoodOrServiceAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_019e64ea-07eb-7b3b-b3c8-504ca0d5d408" xlink:to="loc_us-gaap_TimingOfTransferOfGoodOrServiceAxis_019e64ea-07eb-7f51-98ec-c2fd22ae8cfb" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TimingOfTransferOfGoodOrServiceDomain_019e64ea-07eb-7f51-98ec-c2fd22ae8cfb_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TimingOfTransferOfGoodOrServiceDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_TimingOfTransferOfGoodOrServiceAxis_019e64ea-07eb-7f51-98ec-c2fd22ae8cfb" xlink:to="loc_us-gaap_TimingOfTransferOfGoodOrServiceDomain_019e64ea-07eb-7f51-98ec-c2fd22ae8cfb_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TimingOfTransferOfGoodOrServiceDomain_019e64ea-07eb-78dd-b9f8-e19aa36e11f4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TimingOfTransferOfGoodOrServiceDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_TimingOfTransferOfGoodOrServiceAxis_019e64ea-07eb-7f51-98ec-c2fd22ae8cfb" xlink:to="loc_us-gaap_TimingOfTransferOfGoodOrServiceDomain_019e64ea-07eb-78dd-b9f8-e19aa36e11f4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransferredOverTimeMember_019e64ea-07eb-7c8f-9461-aa25d209ca9f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TransferredOverTimeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TimingOfTransferOfGoodOrServiceDomain_019e64ea-07eb-78dd-b9f8-e19aa36e11f4" xlink:to="loc_us-gaap_TransferredOverTimeMember_019e64ea-07eb-7c8f-9461-aa25d209ca9f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransferredAtPointInTimeMember_019e64ea-07eb-7086-8615-8e67d4763d81" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TransferredAtPointInTimeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TimingOfTransferOfGoodOrServiceDomain_019e64ea-07eb-78dd-b9f8-e19aa36e11f4" xlink:to="loc_us-gaap_TransferredAtPointInTimeMember_019e64ea-07eb-7086-8615-8e67d4763d81" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_019e64ea-07eb-7046-b104-f238492c4e08" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_019e64ea-07eb-7995-ab2d-172ca66b0e4d" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_019e64ea-07eb-7046-b104-f238492c4e08" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.comscore.com/role/RevenueRecognitionTransactionPriceAllocatedtotheRemainingPerformanceObligationsDetails" xlink:type="simple" xlink:href="scor-20260630.xsd#RevenueRecognitionTransactionPriceAllocatedtotheRemainingPerformanceObligationsDetails"/>
  <link:definitionLink xlink:role="http://www.comscore.com/role/RevenueRecognitionTransactionPriceAllocatedtotheRemainingPerformanceObligationsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_019e64ea-07eb-749a-b2a9-a42776edac9d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_019e64ea-07eb-74ca-ad0e-4448f6786983" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_019e64ea-07eb-749a-b2a9-a42776edac9d" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_019e64ea-07eb-74ca-ad0e-4448f6786983" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionStartDateAxis_019e64ea-07eb-77e2-a98c-d83accdf6dd4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionStartDateAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_019e64ea-07eb-74ca-ad0e-4448f6786983" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionStartDateAxis_019e64ea-07eb-77e2-a98c-d83accdf6dd4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligation_019e64ea-07eb-7adf-b4da-dcc3ffb4df49" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevenueRemainingPerformanceObligation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_019e64ea-07eb-749a-b2a9-a42776edac9d" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligation_019e64ea-07eb-7adf-b4da-dcc3ffb4df49" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationPercentage_019e64ea-07eb-704f-b8c9-eb8255b52dfb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevenueRemainingPerformanceObligationPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_019e64ea-07eb-749a-b2a9-a42776edac9d" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligationPercentage_019e64ea-07eb-704f-b8c9-eb8255b52dfb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1_019e64ea-07eb-7576-82ea-968f039d45f6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_019e64ea-07eb-749a-b2a9-a42776edac9d" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1_019e64ea-07eb-7576-82ea-968f039d45f6" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.comscore.com/role/RevenueRecognitionTransactionPriceAllocatedtotheRemainingPerformanceObligationsDetails_1" xlink:type="simple" xlink:href="scor-20260630.xsd#RevenueRecognitionTransactionPriceAllocatedtotheRemainingPerformanceObligationsDetails_1"/>
  <link:definitionLink xlink:role="http://www.comscore.com/role/RevenueRecognitionTransactionPriceAllocatedtotheRemainingPerformanceObligationsDetails_1" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_019e64ea-07eb-749a-b2a9-a42776edac9d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_019e64ea-07eb-74ca-ad0e-4448f6786983" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_019e64ea-07eb-749a-b2a9-a42776edac9d" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_019e64ea-07eb-74ca-ad0e-4448f6786983" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligation_019e64ea-07eb-7adf-b4da-dcc3ffb4df49" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevenueRemainingPerformanceObligation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_019e64ea-07eb-749a-b2a9-a42776edac9d" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligation_019e64ea-07eb-7adf-b4da-dcc3ffb4df49" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationPercentage_019e64ea-07eb-704f-b8c9-eb8255b52dfb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevenueRemainingPerformanceObligationPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_019e64ea-07eb-749a-b2a9-a42776edac9d" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligationPercentage_019e64ea-07eb-704f-b8c9-eb8255b52dfb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1_019e64ea-07eb-7576-82ea-968f039d45f6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_019e64ea-07eb-749a-b2a9-a42776edac9d" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1_019e64ea-07eb-7576-82ea-968f039d45f6" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.comscore.com/role/ConvertibleRedeemablePreferredStockandStockholdersEquityDeficitDetails" xlink:type="simple" xlink:href="scor-20260630.xsd#ConvertibleRedeemablePreferredStockandStockholdersEquityDeficitDetails"/>
  <link:definitionLink xlink:role="http://www.comscore.com/role/ConvertibleRedeemablePreferredStockandStockholdersEquityDeficitDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019e64ea-07eb-7f15-ba76-e98efa1a2497" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_019e64ea-07eb-7c5c-a483-200fc435894a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019e64ea-07eb-7f15-ba76-e98efa1a2497" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_019e64ea-07eb-7c5c-a483-200fc435894a" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsidiarySaleOfStockAxis_019e64ea-07eb-7f7a-9afd-0c309c1ed9c0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsidiarySaleOfStockAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_019e64ea-07eb-7c5c-a483-200fc435894a" xlink:to="loc_us-gaap_SubsidiarySaleOfStockAxis_019e64ea-07eb-7f7a-9afd-0c309c1ed9c0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SaleOfStockNameOfTransactionDomain_019e64ea-07eb-7f7a-9afd-0c309c1ed9c0_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SaleOfStockNameOfTransactionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_SubsidiarySaleOfStockAxis_019e64ea-07eb-7f7a-9afd-0c309c1ed9c0" xlink:to="loc_us-gaap_SaleOfStockNameOfTransactionDomain_019e64ea-07eb-7f7a-9afd-0c309c1ed9c0_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SaleOfStockNameOfTransactionDomain_019e64ea-07eb-7f75-9836-77da27fdcecb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SaleOfStockNameOfTransactionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_SubsidiarySaleOfStockAxis_019e64ea-07eb-7f7a-9afd-0c309c1ed9c0" xlink:to="loc_us-gaap_SaleOfStockNameOfTransactionDomain_019e64ea-07eb-7f75-9836-77da27fdcecb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PrivatePlacementMember_019e64ea-07eb-7f74-81e5-bdcee3e2dbad" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PrivatePlacementMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SaleOfStockNameOfTransactionDomain_019e64ea-07eb-7f75-9836-77da27fdcecb" xlink:to="loc_us-gaap_PrivatePlacementMember_019e64ea-07eb-7f74-81e5-bdcee3e2dbad" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementClassOfStockAxis_019e64ea-07eb-7deb-bcfc-49d60ffaca07" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementClassOfStockAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_019e64ea-07eb-7c5c-a483-200fc435894a" xlink:to="loc_us-gaap_StatementClassOfStockAxis_019e64ea-07eb-7deb-bcfc-49d60ffaca07" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_019e64ea-07eb-7deb-bcfc-49d60ffaca07_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_019e64ea-07eb-7deb-bcfc-49d60ffaca07" xlink:to="loc_us-gaap_ClassOfStockDomain_019e64ea-07eb-7deb-bcfc-49d60ffaca07_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_019e64ea-07eb-7cba-94e8-bf9b229f9b2a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_019e64ea-07eb-7deb-bcfc-49d60ffaca07" xlink:to="loc_us-gaap_ClassOfStockDomain_019e64ea-07eb-7cba-94e8-bf9b229f9b2a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_SeriesBRedeemableConvertiblePreferredStockMember_019e64ea-07eb-78c2-b001-c932ecc02153" xlink:href="scor-20260630.xsd#scor_SeriesBRedeemableConvertiblePreferredStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_019e64ea-07eb-7cba-94e8-bf9b229f9b2a" xlink:to="loc_scor_SeriesBRedeemableConvertiblePreferredStockMember_019e64ea-07eb-78c2-b001-c932ecc02153" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_SeriesCRedeemableConvertiblePreferredStockMember_019e64ea-07eb-70e0-b70c-5f4ad88d5bb8" xlink:href="scor-20260630.xsd#scor_SeriesCRedeemableConvertiblePreferredStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_019e64ea-07eb-7cba-94e8-bf9b229f9b2a" xlink:to="loc_scor_SeriesCRedeemableConvertiblePreferredStockMember_019e64ea-07eb-70e0-b70c-5f4ad88d5bb8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_SeriesBConvertibleRedeemablePreferredStockExchangesForTemporaryEquityMember_019e64ea-07eb-7c16-bc40-ba1e9825ed50" xlink:href="scor-20260630.xsd#scor_SeriesBConvertibleRedeemablePreferredStockExchangesForTemporaryEquityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_019e64ea-07eb-7cba-94e8-bf9b229f9b2a" xlink:to="loc_scor_SeriesBConvertibleRedeemablePreferredStockExchangesForTemporaryEquityMember_019e64ea-07eb-7c16-bc40-ba1e9825ed50" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_SeriesBConvertibleRedeemablePreferredStockExchangedForCommonEquityMember_019e64ea-07eb-7f54-9d7f-71a87d623ce0" xlink:href="scor-20260630.xsd#scor_SeriesBConvertibleRedeemablePreferredStockExchangedForCommonEquityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_019e64ea-07eb-7cba-94e8-bf9b229f9b2a" xlink:to="loc_scor_SeriesBConvertibleRedeemablePreferredStockExchangedForCommonEquityMember_019e64ea-07eb-7f54-9d7f-71a87d623ce0" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_019e64ea-07eb-7db9-ab56-fe3f5077f9bc" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_019e64ea-07eb-7c5c-a483-200fc435894a" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_019e64ea-07eb-7db9-ab56-fe3f5077f9bc" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_019e64ea-07eb-7db9-ab56-fe3f5077f9bc_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_019e64ea-07eb-7db9-ab56-fe3f5077f9bc" xlink:to="loc_us-gaap_EquityComponentDomain_019e64ea-07eb-7db9-ab56-fe3f5077f9bc_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_019e64ea-07eb-744a-bcb1-f0b48bca6146" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_019e64ea-07eb-7db9-ab56-fe3f5077f9bc" xlink:to="loc_us-gaap_EquityComponentDomain_019e64ea-07eb-744a-bcb1-f0b48bca6146" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockMember_019e64ea-07eb-731c-94bb-1e7fd37bc5c7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_019e64ea-07eb-744a-bcb1-f0b48bca6146" xlink:to="loc_us-gaap_CommonStockMember_019e64ea-07eb-731c-94bb-1e7fd37bc5c7" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetainedEarningsMember_019e64ea-07eb-74b7-991d-b998ab971a1b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RetainedEarningsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_019e64ea-07eb-744a-bcb1-f0b48bca6146" xlink:to="loc_us-gaap_RetainedEarningsMember_019e64ea-07eb-74b7-991d-b998ab971a1b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_TemporaryEquityStockIssuedDuringPeriodSharesNewIssues_019e64ea-07eb-7ae0-b175-47421e77289a" xlink:href="scor-20260630.xsd#scor_TemporaryEquityStockIssuedDuringPeriodSharesNewIssues"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019e64ea-07eb-7f15-ba76-e98efa1a2497" xlink:to="loc_scor_TemporaryEquityStockIssuedDuringPeriodSharesNewIssues_019e64ea-07eb-7ae0-b175-47421e77289a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_TemporaryEquityStockIssuedDuringPeriodValueNewIssuesGross_019e64ea-07eb-70f9-a0c3-a782f837c960" xlink:href="scor-20260630.xsd#scor_TemporaryEquityStockIssuedDuringPeriodValueNewIssuesGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019e64ea-07eb-7f15-ba76-e98efa1a2497" xlink:to="loc_scor_TemporaryEquityStockIssuedDuringPeriodValueNewIssuesGross_019e64ea-07eb-70f9-a0c3-a782f837c960" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TemporaryEquityStockIssuedDuringPeriodValueNewIssues_019e64ea-07eb-7705-9f76-7a2ca4c3d4a0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TemporaryEquityStockIssuedDuringPeriodValueNewIssues"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019e64ea-07eb-7f15-ba76-e98efa1a2497" xlink:to="loc_us-gaap_TemporaryEquityStockIssuedDuringPeriodValueNewIssues_019e64ea-07eb-7705-9f76-7a2ca4c3d4a0" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_TemporaryEquityDividendRatePercentage_019e64ea-07eb-7923-83e4-ac3f3c643348" xlink:href="scor-20260630.xsd#scor_TemporaryEquityDividendRatePercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019e64ea-07eb-7f15-ba76-e98efa1a2497" xlink:to="loc_scor_TemporaryEquityDividendRatePercentage_019e64ea-07eb-7923-83e4-ac3f3c643348" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_PreferredStockCumulativeDividendRatePercentage_019e64ea-07eb-7fe8-a39d-ec6a11aaa366" xlink:href="scor-20260630.xsd#scor_PreferredStockCumulativeDividendRatePercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019e64ea-07eb-7f15-ba76-e98efa1a2497" xlink:to="loc_scor_PreferredStockCumulativeDividendRatePercentage_019e64ea-07eb-7fe8-a39d-ec6a11aaa366" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_TemporaryEquityDeferredDividendRatePercentage_019e64ea-07eb-744d-8711-4a613e9dced6" xlink:href="scor-20260630.xsd#scor_TemporaryEquityDeferredDividendRatePercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019e64ea-07eb-7f15-ba76-e98efa1a2497" xlink:to="loc_scor_TemporaryEquityDeferredDividendRatePercentage_019e64ea-07eb-744d-8711-4a613e9dced6" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DividendsPayableCurrentAndNoncurrent_019e64ea-07eb-7bae-a839-234c41ed11a4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DividendsPayableCurrentAndNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019e64ea-07eb-7f15-ba76-e98efa1a2497" xlink:to="loc_us-gaap_DividendsPayableCurrentAndNoncurrent_019e64ea-07eb-7bae-a839-234c41ed11a4" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockConvertibleSharesIssuable_019e64ea-07eb-7487-8fa5-6c4eaf73e0e3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PreferredStockConvertibleSharesIssuable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019e64ea-07eb-7f15-ba76-e98efa1a2497" xlink:to="loc_us-gaap_PreferredStockConvertibleSharesIssuable_019e64ea-07eb-7487-8fa5-6c4eaf73e0e3" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockConvertibleConversionPrice_019e64ea-07eb-7453-8dec-d4bada56cf2b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PreferredStockConvertibleConversionPrice"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019e64ea-07eb-7f15-ba76-e98efa1a2497" xlink:to="loc_us-gaap_PreferredStockConvertibleConversionPrice_019e64ea-07eb-7453-8dec-d4bada56cf2b" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_PreferredStockSpecialDividendThreshold_019e64ea-07eb-772d-91c8-840bfe5a4533" xlink:href="scor-20260630.xsd#scor_PreferredStockSpecialDividendThreshold"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019e64ea-07eb-7f15-ba76-e98efa1a2497" xlink:to="loc_scor_PreferredStockSpecialDividendThreshold_019e64ea-07eb-772d-91c8-840bfe5a4533" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockLiquidationPreferenceValue_019e64ea-07eb-7a26-944f-8cd0525df85e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PreferredStockLiquidationPreferenceValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019e64ea-07eb-7f15-ba76-e98efa1a2497" xlink:to="loc_us-gaap_PreferredStockLiquidationPreferenceValue_019e64ea-07eb-7a26-944f-8cd0525df85e" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_TemporaryEquityStockIssuedDuringPeriodInitialFairValueAfterIssuanceCostsNewIssues_019e64ea-07eb-7267-a653-c58dddcda015" xlink:href="scor-20260630.xsd#scor_TemporaryEquityStockIssuedDuringPeriodInitialFairValueAfterIssuanceCostsNewIssues"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019e64ea-07eb-7f15-ba76-e98efa1a2497" xlink:to="loc_scor_TemporaryEquityStockIssuedDuringPeriodInitialFairValueAfterIssuanceCostsNewIssues_019e64ea-07eb-7267-a653-c58dddcda015" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalIncreaseInCarryingAmountOfRedeemablePreferredStock_019e64ea-07eb-7b16-9a2c-6edca1243eb8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AdjustmentsToAdditionalPaidInCapitalIncreaseInCarryingAmountOfRedeemablePreferredStock"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019e64ea-07eb-7f15-ba76-e98efa1a2497" xlink:to="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalIncreaseInCarryingAmountOfRedeemablePreferredStock_019e64ea-07eb-7b16-9a2c-6edca1243eb8" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_StockExchangeAgreementSharesExchanged_019e64ea-07eb-79c0-ad64-9bb028ba8f92" xlink:href="scor-20260630.xsd#scor_StockExchangeAgreementSharesExchanged"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019e64ea-07eb-7f15-ba76-e98efa1a2497" xlink:to="loc_scor_StockExchangeAgreementSharesExchanged_019e64ea-07eb-79c0-ad64-9bb028ba8f92" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_StockExchangeAgreementNewStockReceived_019e64ea-07eb-7225-9505-63038a3318aa" xlink:href="scor-20260630.xsd#scor_StockExchangeAgreementNewStockReceived"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019e64ea-07eb-7f15-ba76-e98efa1a2497" xlink:to="loc_scor_StockExchangeAgreementNewStockReceived_019e64ea-07eb-7225-9505-63038a3318aa" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TemporaryEquityLiquidationPreference_019e64ea-07eb-7733-81d3-e601dc3f635c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TemporaryEquityLiquidationPreference"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019e64ea-07eb-7f15-ba76-e98efa1a2497" xlink:to="loc_us-gaap_TemporaryEquityLiquidationPreference_019e64ea-07eb-7733-81d3-e601dc3f635c" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_TemporaryEquityLiquidationPreferenceExchanged_019e64ea-07eb-74d4-97f0-d4bfc0c27619" xlink:href="scor-20260630.xsd#scor_TemporaryEquityLiquidationPreferenceExchanged"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019e64ea-07eb-7f15-ba76-e98efa1a2497" xlink:to="loc_scor_TemporaryEquityLiquidationPreferenceExchanged_019e64ea-07eb-74d4-97f0-d4bfc0c27619" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharePrice_019e64ea-07eb-7326-a8dc-1e4be9889e9b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SharePrice"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019e64ea-07eb-7f15-ba76-e98efa1a2497" xlink:to="loc_us-gaap_SharePrice_019e64ea-07eb-7326-a8dc-1e4be9889e9b" xlink:type="arc" order="17"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_TemporaryEquityRecapitalizationTransactionNetShares_019e64ea-07eb-7321-8d93-1c958b672eac" xlink:href="scor-20260630.xsd#scor_TemporaryEquityRecapitalizationTransactionNetShares"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019e64ea-07eb-7f15-ba76-e98efa1a2497" xlink:to="loc_scor_TemporaryEquityRecapitalizationTransactionNetShares_019e64ea-07eb-7321-8d93-1c958b672eac" xlink:type="arc" order="18"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_RecapitalizationTransactionNetShares_019e64ea-07eb-776c-aa24-1f9ee9b3c706" xlink:href="scor-20260630.xsd#scor_RecapitalizationTransactionNetShares"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019e64ea-07eb-7f15-ba76-e98efa1a2497" xlink:to="loc_scor_RecapitalizationTransactionNetShares_019e64ea-07eb-776c-aa24-1f9ee9b3c706" xlink:type="arc" order="19"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_StockExchangeAgreementOneTimeCashPaymentToPreferredStockholders_019e64ea-07eb-7816-b9b6-dc160290b33f" xlink:href="scor-20260630.xsd#scor_StockExchangeAgreementOneTimeCashPaymentToPreferredStockholders"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019e64ea-07eb-7f15-ba76-e98efa1a2497" xlink:to="loc_scor_StockExchangeAgreementOneTimeCashPaymentToPreferredStockholders_019e64ea-07eb-7816-b9b6-dc160290b33f" xlink:type="arc" order="20"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TemporaryEquitySharesAuthorized_019e64ea-07eb-767d-ada9-01218ff8f454" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TemporaryEquitySharesAuthorized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019e64ea-07eb-7f15-ba76-e98efa1a2497" xlink:to="loc_us-gaap_TemporaryEquitySharesAuthorized_019e64ea-07eb-767d-ada9-01218ff8f454" xlink:type="arc" order="21"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockSharesAuthorized_019e64ea-07eb-769f-8b76-1cdb539f879b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PreferredStockSharesAuthorized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019e64ea-07eb-7f15-ba76-e98efa1a2497" xlink:to="loc_us-gaap_PreferredStockSharesAuthorized_019e64ea-07eb-769f-8b76-1cdb539f879b" xlink:type="arc" order="22"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesAuthorized_019e64ea-07eb-763d-b510-227364153b36" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockSharesAuthorized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019e64ea-07eb-7f15-ba76-e98efa1a2497" xlink:to="loc_us-gaap_CommonStockSharesAuthorized_019e64ea-07eb-763d-b510-227364153b36" xlink:type="arc" order="23"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsOfStockIssuanceCosts_019e64ea-07eb-7d92-9d02-517bf34d8ecf" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PaymentsOfStockIssuanceCosts"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019e64ea-07eb-7f15-ba76-e98efa1a2497" xlink:to="loc_us-gaap_PaymentsOfStockIssuanceCosts_019e64ea-07eb-7d92-9d02-517bf34d8ecf" xlink:type="arc" order="24"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_TemporaryEquityCarryingAmountDerecognized_019e64ea-07eb-7d77-b4cc-d06599ec61b4" xlink:href="scor-20260630.xsd#scor_TemporaryEquityCarryingAmountDerecognized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019e64ea-07eb-7f15-ba76-e98efa1a2497" xlink:to="loc_scor_TemporaryEquityCarryingAmountDerecognized_019e64ea-07eb-7d77-b4cc-d06599ec61b4" xlink:type="arc" order="25"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_TemporaryEquityAccruedDividendsLiabilityDerecognized_019e64ea-07eb-7216-ac17-df130c123579" xlink:href="scor-20260630.xsd#scor_TemporaryEquityAccruedDividendsLiabilityDerecognized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019e64ea-07eb-7f15-ba76-e98efa1a2497" xlink:to="loc_scor_TemporaryEquityAccruedDividendsLiabilityDerecognized_019e64ea-07eb-7216-ac17-df130c123579" xlink:type="arc" order="26"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_RecapitalizationTransactionNetValue_019e64ea-07eb-73be-9d63-202ee6b37080" xlink:href="scor-20260630.xsd#scor_RecapitalizationTransactionNetValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019e64ea-07eb-7f15-ba76-e98efa1a2497" xlink:to="loc_scor_RecapitalizationTransactionNetValue_019e64ea-07eb-73be-9d63-202ee6b37080" xlink:type="arc" order="27"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_PreferredStockConvertibleMaximumOwnershipAfterConversion_019e64ea-07eb-7df9-9dc7-427e21b617b5" xlink:href="scor-20260630.xsd#scor_PreferredStockConvertibleMaximumOwnershipAfterConversion"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019e64ea-07eb-7f15-ba76-e98efa1a2497" xlink:to="loc_scor_PreferredStockConvertibleMaximumOwnershipAfterConversion_019e64ea-07eb-7df9-9dc7-427e21b617b5" xlink:type="arc" order="28"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockConvertibleConversionRatio_019e64ea-07eb-732e-aaa3-2c7ca1668363" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PreferredStockConvertibleConversionRatio"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019e64ea-07eb-7f15-ba76-e98efa1a2497" xlink:to="loc_us-gaap_PreferredStockConvertibleConversionRatio_019e64ea-07eb-732e-aaa3-2c7ca1668363" xlink:type="arc" order="29"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesConversionOfConvertibleSecurities_019e64ea-07eb-7c89-b032-d67806ae019a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockIssuedDuringPeriodSharesConversionOfConvertibleSecurities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019e64ea-07eb-7f15-ba76-e98efa1a2497" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesConversionOfConvertibleSecurities_019e64ea-07eb-7c89-b032-d67806ae019a" xlink:type="arc" order="30"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.comscore.com/role/DebtNarrativeDetails" xlink:type="simple" xlink:href="scor-20260630.xsd#DebtNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.comscore.com/role/DebtNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfCapitalizationLongtermDebtLineItems_019e64ea-07eb-7c2f-a973-726294b660d2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfCapitalizationLongtermDebtLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfCapitalizationLongtermDebtTable_019e64ea-07eb-7ea4-9afd-7598a52c81d8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfCapitalizationLongtermDebtTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ScheduleOfCapitalizationLongtermDebtLineItems_019e64ea-07eb-7c2f-a973-726294b660d2" xlink:to="loc_us-gaap_ScheduleOfCapitalizationLongtermDebtTable_019e64ea-07eb-7ea4-9afd-7598a52c81d8" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_019e64ea-07eb-7491-87dc-0c11d1b7d52f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfCapitalizationLongtermDebtTable_019e64ea-07eb-7ea4-9afd-7598a52c81d8" xlink:to="loc_us-gaap_DebtInstrumentAxis_019e64ea-07eb-7491-87dc-0c11d1b7d52f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_019e64ea-07eb-7491-87dc-0c11d1b7d52f_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_019e64ea-07eb-7491-87dc-0c11d1b7d52f" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_019e64ea-07eb-7491-87dc-0c11d1b7d52f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_019e64ea-07eb-7337-b4eb-22a05de22ae3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_019e64ea-07eb-7491-87dc-0c11d1b7d52f" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_019e64ea-07eb-7337-b4eb-22a05de22ae3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_CreditAgreementMember_019e64ea-07eb-7cf2-af47-65ff457e0d3f" xlink:href="scor-20260630.xsd#scor_CreditAgreementMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_019e64ea-07eb-7337-b4eb-22a05de22ae3" xlink:to="loc_scor_CreditAgreementMember_019e64ea-07eb-7cf2-af47-65ff457e0d3f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_TermLoanMember_019e64ea-07eb-7ce5-9df1-e8e28652ad7c" xlink:href="scor-20260630.xsd#scor_TermLoanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_019e64ea-07eb-7337-b4eb-22a05de22ae3" xlink:to="loc_scor_TermLoanMember_019e64ea-07eb-7ce5-9df1-e8e28652ad7c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_019e64ea-07eb-72a9-a529-0a0e58f5de94" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfCapitalizationLongtermDebtTable_019e64ea-07eb-7ea4-9afd-7598a52c81d8" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_019e64ea-07eb-72a9-a529-0a0e58f5de94" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_019e64ea-07eb-72a9-a529-0a0e58f5de94_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_019e64ea-07eb-72a9-a529-0a0e58f5de94" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_019e64ea-07eb-72a9-a529-0a0e58f5de94_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_019e64ea-07eb-7c96-b45e-80982be73fc0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_019e64ea-07eb-72a9-a529-0a0e58f5de94" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_019e64ea-07eb-7c96-b45e-80982be73fc0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SecuredDebtMember_019e64ea-07eb-7a6c-9cf4-2aa8ed3389b5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SecuredDebtMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_019e64ea-07eb-7c96-b45e-80982be73fc0" xlink:to="loc_us-gaap_SecuredDebtMember_019e64ea-07eb-7a6c-9cf4-2aa8ed3389b5" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditMember_019e64ea-07eb-7e6b-89d6-9e2cbb25480a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LineOfCreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_019e64ea-07eb-7c96-b45e-80982be73fc0" xlink:to="loc_us-gaap_LineOfCreditMember_019e64ea-07eb-7e6b-89d6-9e2cbb25480a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityAxis_019e64ea-07eb-7065-b3a0-e63f42beabf3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CreditFacilityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfCapitalizationLongtermDebtTable_019e64ea-07eb-7ea4-9afd-7598a52c81d8" xlink:to="loc_us-gaap_CreditFacilityAxis_019e64ea-07eb-7065-b3a0-e63f42beabf3" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityDomain_019e64ea-07eb-7065-b3a0-e63f42beabf3_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CreditFacilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CreditFacilityAxis_019e64ea-07eb-7065-b3a0-e63f42beabf3" xlink:to="loc_us-gaap_CreditFacilityDomain_019e64ea-07eb-7065-b3a0-e63f42beabf3_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityDomain_019e64ea-07eb-7f81-8845-2f3dbe27ba12" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CreditFacilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CreditFacilityAxis_019e64ea-07eb-7065-b3a0-e63f42beabf3" xlink:to="loc_us-gaap_CreditFacilityDomain_019e64ea-07eb-7f81-8845-2f3dbe27ba12" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevolvingCreditFacilityMember_019e64ea-07eb-7783-b77b-33bc5444c699" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevolvingCreditFacilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_019e64ea-07eb-7f81-8845-2f3dbe27ba12" xlink:to="loc_us-gaap_RevolvingCreditFacilityMember_019e64ea-07eb-7783-b77b-33bc5444c699" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateAxis_019e64ea-07eb-7260-a240-0fa71b242432" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_VariableRateAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfCapitalizationLongtermDebtTable_019e64ea-07eb-7ea4-9afd-7598a52c81d8" xlink:to="loc_us-gaap_VariableRateAxis_019e64ea-07eb-7260-a240-0fa71b242432" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateDomain_019e64ea-07eb-7260-a240-0fa71b242432_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_VariableRateDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_VariableRateAxis_019e64ea-07eb-7260-a240-0fa71b242432" xlink:to="loc_us-gaap_VariableRateDomain_019e64ea-07eb-7260-a240-0fa71b242432_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateDomain_019e64ea-07eb-7dac-8439-bd560dde288f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_VariableRateDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_VariableRateAxis_019e64ea-07eb-7260-a240-0fa71b242432" xlink:to="loc_us-gaap_VariableRateDomain_019e64ea-07eb-7dac-8439-bd560dde288f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SecuredOvernightFinancingRateSofrOvernightIndexSwapRateMember_019e64ea-07eb-7b03-8c70-e22192324b0a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SecuredOvernightFinancingRateSofrOvernightIndexSwapRateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableRateDomain_019e64ea-07eb-7dac-8439-bd560dde288f" xlink:to="loc_us-gaap_SecuredOvernightFinancingRateSofrOvernightIndexSwapRateMember_019e64ea-07eb-7b03-8c70-e22192324b0a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_ReferenceRateMember_019e64ea-07eb-776f-8b11-8db56df6a93c" xlink:href="scor-20260630.xsd#scor_ReferenceRateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableRateDomain_019e64ea-07eb-7dac-8439-bd560dde288f" xlink:to="loc_scor_ReferenceRateMember_019e64ea-07eb-776f-8b11-8db56df6a93c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardDateAxis_019e64ea-07eb-754c-89d5-73e493035e88" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AwardDateAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfCapitalizationLongtermDebtTable_019e64ea-07eb-7ea4-9afd-7598a52c81d8" xlink:to="loc_us-gaap_AwardDateAxis_019e64ea-07eb-754c-89d5-73e493035e88" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardDateDomain_019e64ea-07eb-754c-89d5-73e493035e88_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AwardDateDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardDateAxis_019e64ea-07eb-754c-89d5-73e493035e88" xlink:to="loc_us-gaap_AwardDateDomain_019e64ea-07eb-754c-89d5-73e493035e88_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardDateDomain_019e64ea-07eb-7ae0-8313-897c57decab0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AwardDateDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardDateAxis_019e64ea-07eb-754c-89d5-73e493035e88" xlink:to="loc_us-gaap_AwardDateDomain_019e64ea-07eb-7ae0-8313-897c57decab0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_BeforeFirstAnniversaryMember_019e64ea-07eb-7830-8be4-976bc33ef7e0" xlink:href="scor-20260630.xsd#scor_BeforeFirstAnniversaryMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AwardDateDomain_019e64ea-07eb-7ae0-8313-897c57decab0" xlink:to="loc_scor_BeforeFirstAnniversaryMember_019e64ea-07eb-7830-8be4-976bc33ef7e0" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_BeforeSecondAnniversaryMember_019e64ea-07eb-7e44-8aba-03e1653d03c7" xlink:href="scor-20260630.xsd#scor_BeforeSecondAnniversaryMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AwardDateDomain_019e64ea-07eb-7ae0-8313-897c57decab0" xlink:to="loc_scor_BeforeSecondAnniversaryMember_019e64ea-07eb-7e44-8aba-03e1653d03c7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_DebtTermAxis_019e64ea-07eb-7c1f-b220-962c6b703d7f" xlink:href="scor-20260630.xsd#scor_DebtTermAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfCapitalizationLongtermDebtTable_019e64ea-07eb-7ea4-9afd-7598a52c81d8" xlink:to="loc_scor_DebtTermAxis_019e64ea-07eb-7c1f-b220-962c6b703d7f" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_DebtTermDomain_019e64ea-07eb-7c1f-b220-962c6b703d7f_default" xlink:href="scor-20260630.xsd#scor_DebtTermDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_scor_DebtTermAxis_019e64ea-07eb-7c1f-b220-962c6b703d7f" xlink:to="loc_scor_DebtTermDomain_019e64ea-07eb-7c1f-b220-962c6b703d7f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_DebtTermDomain_019e64ea-07eb-7ef3-9200-57c5d702753c" xlink:href="scor-20260630.xsd#scor_DebtTermDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_scor_DebtTermAxis_019e64ea-07eb-7c1f-b220-962c6b703d7f" xlink:to="loc_scor_DebtTermDomain_019e64ea-07eb-7ef3-9200-57c5d702753c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_DebtInstrumentIfTotalLeverageRatioIsGreaterThan2.25Member_019e64ea-07eb-7d20-ae89-1498709540ec" xlink:href="scor-20260630.xsd#scor_DebtInstrumentIfTotalLeverageRatioIsGreaterThan2.25Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_scor_DebtTermDomain_019e64ea-07eb-7ef3-9200-57c5d702753c" xlink:to="loc_scor_DebtInstrumentIfTotalLeverageRatioIsGreaterThan2.25Member_019e64ea-07eb-7d20-ae89-1498709540ec" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_DebtInstrumentIfTotalLeverageRatioIsEqualToOrLessThan2.25AndGreaterThan1.75Member_019e64ea-07eb-7867-825b-230a1cd356bc" xlink:href="scor-20260630.xsd#scor_DebtInstrumentIfTotalLeverageRatioIsEqualToOrLessThan2.25AndGreaterThan1.75Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_scor_DebtTermDomain_019e64ea-07eb-7ef3-9200-57c5d702753c" xlink:to="loc_scor_DebtInstrumentIfTotalLeverageRatioIsEqualToOrLessThan2.25AndGreaterThan1.75Member_019e64ea-07eb-7867-825b-230a1cd356bc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_DebtInstrumentIfTotalLeverageRatioIsEqualToOrLessThan1.75AndGreaterThan1.25Member_019e64ea-07eb-7143-9dd4-4d745ac1b3bd" xlink:href="scor-20260630.xsd#scor_DebtInstrumentIfTotalLeverageRatioIsEqualToOrLessThan1.75AndGreaterThan1.25Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_scor_DebtTermDomain_019e64ea-07eb-7ef3-9200-57c5d702753c" xlink:to="loc_scor_DebtInstrumentIfTotalLeverageRatioIsEqualToOrLessThan1.75AndGreaterThan1.25Member_019e64ea-07eb-7143-9dd4-4d745ac1b3bd" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_DebtInstrumentIfTotalLeverageRatioIsEqualToOrLessThan1.25Member_019e64ea-07eb-735d-8f5b-e46989857bea" xlink:href="scor-20260630.xsd#scor_DebtInstrumentIfTotalLeverageRatioIsEqualToOrLessThan1.25Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_scor_DebtTermDomain_019e64ea-07eb-7ef3-9200-57c5d702753c" xlink:to="loc_scor_DebtInstrumentIfTotalLeverageRatioIsEqualToOrLessThan1.25Member_019e64ea-07eb-735d-8f5b-e46989857bea" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_DebtInstrumentIfTotalLeverageRatioIsEqualToOrLessThan3.25Member_019e64ea-07eb-70a9-b21b-a53531b73ca6" xlink:href="scor-20260630.xsd#scor_DebtInstrumentIfTotalLeverageRatioIsEqualToOrLessThan3.25Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_scor_DebtTermDomain_019e64ea-07eb-7ef3-9200-57c5d702753c" xlink:to="loc_scor_DebtInstrumentIfTotalLeverageRatioIsEqualToOrLessThan3.25Member_019e64ea-07eb-70a9-b21b-a53531b73ca6" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTerm_019e64ea-07eb-7a57-b28c-4db1f0ae479a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentTerm"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfCapitalizationLongtermDebtLineItems_019e64ea-07eb-7c2f-a973-726294b660d2" xlink:to="loc_us-gaap_DebtInstrumentTerm_019e64ea-07eb-7a57-b28c-4db1f0ae479a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentCarryingAmount_019e64ea-07eb-7dd0-82d4-dedd73b70def" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentCarryingAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfCapitalizationLongtermDebtLineItems_019e64ea-07eb-7c2f-a973-726294b660d2" xlink:to="loc_us-gaap_DebtInstrumentCarryingAmount_019e64ea-07eb-7dd0-82d4-dedd73b70def" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentFaceAmount_019e64ea-07eb-751c-83e1-43367f7b54a8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentFaceAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfCapitalizationLongtermDebtLineItems_019e64ea-07eb-7c2f-a973-726294b660d2" xlink:to="loc_us-gaap_DebtInstrumentFaceAmount_019e64ea-07eb-751c-83e1-43367f7b54a8" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_019e64ea-07eb-723d-aacc-db56f5b7e9d4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfCapitalizationLongtermDebtLineItems_019e64ea-07eb-7c2f-a973-726294b660d2" xlink:to="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_019e64ea-07eb-723d-aacc-db56f5b7e9d4" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_DebtInstrumentFloorOnVariableRate_019e64ea-07eb-70f2-8f74-79b90d42e383" xlink:href="scor-20260630.xsd#scor_DebtInstrumentFloorOnVariableRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfCapitalizationLongtermDebtLineItems_019e64ea-07eb-7c2f-a973-726294b660d2" xlink:to="loc_scor_DebtInstrumentFloorOnVariableRate_019e64ea-07eb-70f2-8f74-79b90d42e383" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_019e64ea-07eb-7513-8a33-c4110655a468" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentBasisSpreadOnVariableRate1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfCapitalizationLongtermDebtLineItems_019e64ea-07eb-7c2f-a973-726294b660d2" xlink:to="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_019e64ea-07eb-7513-8a33-c4110655a468" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityUnusedCapacityCommitmentFeePercentage_019e64ea-07eb-71b7-88f6-4a4095b11416" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LineOfCreditFacilityUnusedCapacityCommitmentFeePercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfCapitalizationLongtermDebtLineItems_019e64ea-07eb-7c2f-a973-726294b660d2" xlink:to="loc_us-gaap_LineOfCreditFacilityUnusedCapacityCommitmentFeePercentage_019e64ea-07eb-71b7-88f6-4a4095b11416" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_DebtInstrumentPrepaymentPremiumPercentage_019e64ea-07eb-7dbf-b001-7f9da051481d" xlink:href="scor-20260630.xsd#scor_DebtInstrumentPrepaymentPremiumPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfCapitalizationLongtermDebtLineItems_019e64ea-07eb-7c2f-a973-726294b660d2" xlink:to="loc_scor_DebtInstrumentPrepaymentPremiumPercentage_019e64ea-07eb-7dbf-b001-7f9da051481d" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_DebtInstrumentTermThresholdTotalLeverageRatioMinimum_019e64ea-07eb-7a02-b978-d1fe9a5c8930" xlink:href="scor-20260630.xsd#scor_DebtInstrumentTermThresholdTotalLeverageRatioMinimum"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfCapitalizationLongtermDebtLineItems_019e64ea-07eb-7c2f-a973-726294b660d2" xlink:to="loc_scor_DebtInstrumentTermThresholdTotalLeverageRatioMinimum_019e64ea-07eb-7a02-b978-d1fe9a5c8930" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_DebtInstrumentTermThresholdTotalLeverageRatioMaximum_019e64ea-07eb-7b9b-8e17-6f384a56e48a" xlink:href="scor-20260630.xsd#scor_DebtInstrumentTermThresholdTotalLeverageRatioMaximum"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfCapitalizationLongtermDebtLineItems_019e64ea-07eb-7c2f-a973-726294b660d2" xlink:to="loc_scor_DebtInstrumentTermThresholdTotalLeverageRatioMaximum_019e64ea-07eb-7b9b-8e17-6f384a56e48a" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_DebtInstrumentTermPercentOfExcessCashFlowIfRequiredThresholdLeverageRatioIsMaintained_019e64ea-07eb-78b7-a4b7-74e0ed774be9" xlink:href="scor-20260630.xsd#scor_DebtInstrumentTermPercentOfExcessCashFlowIfRequiredThresholdLeverageRatioIsMaintained"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfCapitalizationLongtermDebtLineItems_019e64ea-07eb-7c2f-a973-726294b660d2" xlink:to="loc_scor_DebtInstrumentTermPercentOfExcessCashFlowIfRequiredThresholdLeverageRatioIsMaintained_019e64ea-07eb-78b7-a4b7-74e0ed774be9" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_DebtInstrumentCovenantMinimumLiquidityThreshold_019f226e-992a-785a-ba1c-19c0305becde" xlink:href="scor-20260630.xsd#scor_DebtInstrumentCovenantMinimumLiquidityThreshold"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfCapitalizationLongtermDebtLineItems_019e64ea-07eb-7c2f-a973-726294b660d2" xlink:to="loc_scor_DebtInstrumentCovenantMinimumLiquidityThreshold_019f226e-992a-785a-ba1c-19c0305becde" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentInterestRateEffectivePercentage_019e64ea-07eb-7614-8639-e22c30879899" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentInterestRateEffectivePercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfCapitalizationLongtermDebtLineItems_019e64ea-07eb-7c2f-a973-726294b660d2" xlink:to="loc_us-gaap_DebtInstrumentInterestRateEffectivePercentage_019e64ea-07eb-7614-8639-e22c30879899" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsOfDebtExtinguishmentCosts_019e64ea-07eb-7163-8c35-640f247a81a7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PaymentsOfDebtExtinguishmentCosts"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfCapitalizationLongtermDebtLineItems_019e64ea-07eb-7c2f-a973-726294b660d2" xlink:to="loc_us-gaap_PaymentsOfDebtExtinguishmentCosts_019e64ea-07eb-7163-8c35-640f247a81a7" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_GainLossOnExtinguishmentOfDebtNonCash_019e64ea-07eb-7123-820a-bdd5dca493f0" xlink:href="scor-20260630.xsd#scor_GainLossOnExtinguishmentOfDebtNonCash"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfCapitalizationLongtermDebtLineItems_019e64ea-07eb-7c2f-a973-726294b660d2" xlink:to="loc_scor_GainLossOnExtinguishmentOfDebtNonCash_019e64ea-07eb-7123-820a-bdd5dca493f0" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RepaymentsOfSecuredDebt_019ed98d-9ddd-7079-ad22-36f73ad662ac" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RepaymentsOfSecuredDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfCapitalizationLongtermDebtLineItems_019e64ea-07eb-7c2f-a973-726294b660d2" xlink:to="loc_us-gaap_RepaymentsOfSecuredDebt_019ed98d-9ddd-7079-ad22-36f73ad662ac" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentRepaidPrincipal_019f7153-9319-7d14-8456-cf9dac9a57ae" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentRepaidPrincipal"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfCapitalizationLongtermDebtLineItems_019e64ea-07eb-7c2f-a973-726294b660d2" xlink:to="loc_us-gaap_DebtInstrumentRepaidPrincipal_019f7153-9319-7d14-8456-cf9dac9a57ae" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_RepaymentOfAccruedInterest_019ed988-d0bb-7d7e-8821-8446d0167f9c" xlink:href="scor-20260630.xsd#scor_RepaymentOfAccruedInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfCapitalizationLongtermDebtLineItems_019e64ea-07eb-7c2f-a973-726294b660d2" xlink:to="loc_scor_RepaymentOfAccruedInterest_019ed988-d0bb-7d7e-8821-8446d0167f9c" xlink:type="arc" order="17"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainsLossesOnExtinguishmentOfDebt_019e64ea-07eb-7f7d-9e95-637d0e9b53be" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_GainsLossesOnExtinguishmentOfDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfCapitalizationLongtermDebtLineItems_019e64ea-07eb-7c2f-a973-726294b660d2" xlink:to="loc_us-gaap_GainsLossesOnExtinguishmentOfDebt_019e64ea-07eb-7f7d-9e95-637d0e9b53be" xlink:type="arc" order="18"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_UnamortizedDebtDiscountAndDebtIssuanceCostsWriteoff_019ebadd-dafc-7e53-930c-c4afa7272dd8" xlink:href="scor-20260630.xsd#scor_UnamortizedDebtDiscountAndDebtIssuanceCostsWriteoff"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfCapitalizationLongtermDebtLineItems_019e64ea-07eb-7c2f-a973-726294b660d2" xlink:to="loc_scor_UnamortizedDebtDiscountAndDebtIssuanceCostsWriteoff_019ebadd-dafc-7e53-930c-c4afa7272dd8" xlink:type="arc" order="19"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.comscore.com/role/FairValueMeasurementsDetails" xlink:type="simple" xlink:href="scor-20260630.xsd#FairValueMeasurementsDetails"/>
  <link:definitionLink xlink:role="http://www.comscore.com/role/FairValueMeasurementsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueOptionQuantitativeDisclosuresLineItems_019e64ea-07eb-7ff7-bc4e-cab4d1bbaf8f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueOptionQuantitativeDisclosuresLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueOptionQuantitativeDisclosuresTable_019e64ea-07eb-71e7-9eac-9ad7a16f4d50" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueOptionQuantitativeDisclosuresTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueOptionQuantitativeDisclosuresLineItems_019e64ea-07eb-7ff7-bc4e-cab4d1bbaf8f" xlink:to="loc_us-gaap_FairValueOptionQuantitativeDisclosuresTable_019e64ea-07eb-71e7-9eac-9ad7a16f4d50" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementClassOfStockAxis_019e64ea-07eb-7d27-924b-43ceb26c8de3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementClassOfStockAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueOptionQuantitativeDisclosuresTable_019e64ea-07eb-71e7-9eac-9ad7a16f4d50" xlink:to="loc_us-gaap_StatementClassOfStockAxis_019e64ea-07eb-7d27-924b-43ceb26c8de3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_019e64ea-07eb-7d27-924b-43ceb26c8de3_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_019e64ea-07eb-7d27-924b-43ceb26c8de3" xlink:to="loc_us-gaap_ClassOfStockDomain_019e64ea-07eb-7d27-924b-43ceb26c8de3_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_019e64ea-07eb-767d-97b5-1952867007f8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_019e64ea-07eb-7d27-924b-43ceb26c8de3" xlink:to="loc_us-gaap_ClassOfStockDomain_019e64ea-07eb-767d-97b5-1952867007f8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_SeriesCRedeemableConvertiblePreferredStockMember_019e64ea-07eb-7314-9527-7d8e13aa117f" xlink:href="scor-20260630.xsd#scor_SeriesCRedeemableConvertiblePreferredStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_019e64ea-07eb-767d-97b5-1952867007f8" xlink:to="loc_scor_SeriesCRedeemableConvertiblePreferredStockMember_019e64ea-07eb-7314-9527-7d8e13aa117f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_019e64ea-07eb-723d-a82a-307fdeb08ca3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueOptionQuantitativeDisclosuresTable_019e64ea-07eb-71e7-9eac-9ad7a16f4d50" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_019e64ea-07eb-723d-a82a-307fdeb08ca3" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_019e64ea-07eb-723d-a82a-307fdeb08ca3_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_019e64ea-07eb-723d-a82a-307fdeb08ca3" xlink:to="loc_us-gaap_EquityComponentDomain_019e64ea-07eb-723d-a82a-307fdeb08ca3_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_019e64ea-07eb-7300-b4a4-6d948aa2cdfa" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_019e64ea-07eb-723d-a82a-307fdeb08ca3" xlink:to="loc_us-gaap_EquityComponentDomain_019e64ea-07eb-7300-b4a4-6d948aa2cdfa" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockMember_019e64ea-07eb-77f4-8c52-b4db52b1a190" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_019e64ea-07eb-7300-b4a4-6d948aa2cdfa" xlink:to="loc_us-gaap_CommonStockMember_019e64ea-07eb-77f4-8c52-b4db52b1a190" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdditionalPaidInCapitalMember_019e64ea-07eb-781f-b878-8a40cda9cbdb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AdditionalPaidInCapitalMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_019e64ea-07eb-7300-b4a4-6d948aa2cdfa" xlink:to="loc_us-gaap_AdditionalPaidInCapitalMember_019e64ea-07eb-781f-b878-8a40cda9cbdb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TemporaryEquityCarryingAmountAttributableToParent_019e64ea-07eb-7f62-8955-6039bf936739" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TemporaryEquityCarryingAmountAttributableToParent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueOptionQuantitativeDisclosuresLineItems_019e64ea-07eb-7ff7-bc4e-cab4d1bbaf8f" xlink:to="loc_us-gaap_TemporaryEquityCarryingAmountAttributableToParent_019e64ea-07eb-7f62-8955-6039bf936739" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityFairValueDisclosure_019e64ea-07eb-7c81-973e-e96a3d34d2ee" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquityFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueOptionQuantitativeDisclosuresLineItems_019e64ea-07eb-7ff7-bc4e-cab4d1bbaf8f" xlink:to="loc_us-gaap_EquityFairValueDisclosure_019e64ea-07eb-7c81-973e-e96a3d34d2ee" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_RecapitalizationTransactionNetValue_019e64ea-07eb-7d0a-b4f6-5c0b400c20d3" xlink:href="scor-20260630.xsd#scor_RecapitalizationTransactionNetValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueOptionQuantitativeDisclosuresLineItems_019e64ea-07eb-7ff7-bc4e-cab4d1bbaf8f" xlink:to="loc_scor_RecapitalizationTransactionNetValue_019e64ea-07eb-7d0a-b4f6-5c0b400c20d3" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.comscore.com/role/RelatedPartyTransactionsNarrativeDetails" xlink:type="simple" xlink:href="scor-20260630.xsd#RelatedPartyTransactionsNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.comscore.com/role/RelatedPartyTransactionsNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionLineItems_019e64ea-08cd-73b7-a496-1ac8e8ee0329" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyTransactionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_019e64ea-07eb-7b8f-83a0-3da0ad7b3344" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_019e64ea-08cd-73b7-a496-1ac8e8ee0329" xlink:to="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_019e64ea-07eb-7b8f-83a0-3da0ad7b3344" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CounterpartyNameAxis_019e64ea-07eb-7748-826d-4034ce732e14" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_CounterpartyNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_019e64ea-07eb-7b8f-83a0-3da0ad7b3344" xlink:to="loc_srt_CounterpartyNameAxis_019e64ea-07eb-7748-826d-4034ce732e14" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_019e64ea-07eb-7748-826d-4034ce732e14_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CounterpartyNameAxis_019e64ea-07eb-7748-826d-4034ce732e14" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_019e64ea-07eb-7748-826d-4034ce732e14_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_019e64ea-07eb-725d-9889-4f305f7cce10" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CounterpartyNameAxis_019e64ea-07eb-7748-826d-4034ce732e14" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_019e64ea-07eb-725d-9889-4f305f7cce10" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_CharterCommunicationsHoldingCompanyLLCMember_019e64ea-07eb-70f3-bdf9-d5131d6c23ba" xlink:href="scor-20260630.xsd#scor_CharterCommunicationsHoldingCompanyLLCMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_019e64ea-07eb-725d-9889-4f305f7cce10" xlink:to="loc_scor_CharterCommunicationsHoldingCompanyLLCMember_019e64ea-07eb-70f3-bdf9-d5131d6c23ba" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_PineInvestorLLCMember_019e64ea-07eb-727a-95d7-9083bd8bc6a2" xlink:href="scor-20260630.xsd#scor_PineInvestorLLCMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_019e64ea-07eb-725d-9889-4f305f7cce10" xlink:to="loc_scor_PineInvestorLLCMember_019e64ea-07eb-727a-95d7-9083bd8bc6a2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_QurateRetailIncMember_019e64ea-07eb-7fc0-91cc-5721d6e500c0" xlink:href="scor-20260630.xsd#scor_QurateRetailIncMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_019e64ea-07eb-725d-9889-4f305f7cce10" xlink:to="loc_scor_QurateRetailIncMember_019e64ea-07eb-7fc0-91cc-5721d6e500c0" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_LibertyMember_019e64ea-07eb-7a71-abcc-7587637c5a54" xlink:href="scor-20260630.xsd#scor_LibertyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_019e64ea-07eb-725d-9889-4f305f7cce10" xlink:to="loc_scor_LibertyMember_019e64ea-07eb-7a71-abcc-7587637c5a54" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_CharterCommunicationsOperatingLLCMember_019e64ea-07eb-7e83-b38c-209dd778758c" xlink:href="scor-20260630.xsd#scor_CharterCommunicationsOperatingLLCMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_019e64ea-07eb-725d-9889-4f305f7cce10" xlink:to="loc_scor_CharterCommunicationsOperatingLLCMember_019e64ea-07eb-7e83-b38c-209dd778758c" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_DirectorsOfficersMember_019e64ea-07eb-7a6a-aacb-f65334ce2cdf" xlink:href="scor-20260630.xsd#scor_DirectorsOfficersMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_019e64ea-07eb-725d-9889-4f305f7cce10" xlink:to="loc_scor_DirectorsOfficersMember_019e64ea-07eb-7a6a-aacb-f65334ce2cdf" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_WPPplcMember_019e64ea-07eb-72df-bd57-33fad942e285" xlink:href="scor-20260630.xsd#scor_WPPplcMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_019e64ea-07eb-725d-9889-4f305f7cce10" xlink:to="loc_scor_WPPplcMember_019e64ea-07eb-72df-bd57-33fad942e285" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019e64ea-07eb-720d-9890-242ce02cb0d2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_019e64ea-07eb-7b8f-83a0-3da0ad7b3344" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019e64ea-07eb-720d-9890-242ce02cb0d2" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_019e64ea-07eb-720d-9890-242ce02cb0d2_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019e64ea-07eb-720d-9890-242ce02cb0d2" xlink:to="loc_us-gaap_RelatedPartyDomain_019e64ea-07eb-720d-9890-242ce02cb0d2_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_019e64ea-07eb-7c57-a588-fc32c13a5128" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019e64ea-07eb-720d-9890-242ce02cb0d2" xlink:to="loc_us-gaap_RelatedPartyDomain_019e64ea-07eb-7c57-a588-fc32c13a5128" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyMember_019e64ea-07eb-7436-a31f-0d666490926f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_019e64ea-07eb-7c57-a588-fc32c13a5128" xlink:to="loc_us-gaap_RelatedPartyMember_019e64ea-07eb-7436-a31f-0d666490926f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementClassOfStockAxis_019e64ea-07eb-70b1-83f9-4ad8024b6efe" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementClassOfStockAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_019e64ea-07eb-7b8f-83a0-3da0ad7b3344" xlink:to="loc_us-gaap_StatementClassOfStockAxis_019e64ea-07eb-70b1-83f9-4ad8024b6efe" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_019e64ea-07eb-70b1-83f9-4ad8024b6efe_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_019e64ea-07eb-70b1-83f9-4ad8024b6efe" xlink:to="loc_us-gaap_ClassOfStockDomain_019e64ea-07eb-70b1-83f9-4ad8024b6efe_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_019e64ea-07eb-72ac-8e22-01f3983cf477" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_019e64ea-07eb-70b1-83f9-4ad8024b6efe" xlink:to="loc_us-gaap_ClassOfStockDomain_019e64ea-07eb-72ac-8e22-01f3983cf477" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_SeriesBRedeemableConvertiblePreferredStockMember_019e64ea-07eb-70c2-87e0-2bdbfbd6920c" xlink:href="scor-20260630.xsd#scor_SeriesBRedeemableConvertiblePreferredStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_019e64ea-07eb-72ac-8e22-01f3983cf477" xlink:to="loc_scor_SeriesBRedeemableConvertiblePreferredStockMember_019e64ea-07eb-70c2-87e0-2bdbfbd6920c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_SeriesCRedeemableConvertiblePreferredStockMember_019e64ea-07eb-7475-9cfe-0e5892252ede" xlink:href="scor-20260630.xsd#scor_SeriesCRedeemableConvertiblePreferredStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_019e64ea-07eb-72ac-8e22-01f3983cf477" xlink:to="loc_scor_SeriesCRedeemableConvertiblePreferredStockMember_019e64ea-07eb-7475-9cfe-0e5892252ede" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_ExchangeCommonStockMember_019e64ea-08cd-7ec6-b5d4-50c58c08f1aa" xlink:href="scor-20260630.xsd#scor_ExchangeCommonStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_019e64ea-07eb-72ac-8e22-01f3983cf477" xlink:to="loc_scor_ExchangeCommonStockMember_019e64ea-08cd-7ec6-b5d4-50c58c08f1aa" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_019e64ea-08cd-7eac-a11e-a5e183e9cf21" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_019e64ea-07eb-7b8f-83a0-3da0ad7b3344" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_019e64ea-08cd-7eac-a11e-a5e183e9cf21" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_019e64ea-08cd-7eac-a11e-a5e183e9cf21_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_019e64ea-08cd-7eac-a11e-a5e183e9cf21" xlink:to="loc_us-gaap_EquityComponentDomain_019e64ea-08cd-7eac-a11e-a5e183e9cf21_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_019e64ea-08cd-73e3-a6b5-734dc8d1abe9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_019e64ea-08cd-7eac-a11e-a5e183e9cf21" xlink:to="loc_us-gaap_EquityComponentDomain_019e64ea-08cd-73e3-a6b5-734dc8d1abe9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockMember_019e64ea-08cd-7ea1-8427-0fc2883b68d3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_019e64ea-08cd-73e3-a6b5-734dc8d1abe9" xlink:to="loc_us-gaap_CommonStockMember_019e64ea-08cd-7ea1-8427-0fc2883b68d3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_TemporaryEquityPercentageOfInterestHeld_019e64ea-08cd-72d4-b5ce-a89700796563" xlink:href="scor-20260630.xsd#scor_TemporaryEquityPercentageOfInterestHeld"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_019e64ea-08cd-73b7-a496-1ac8e8ee0329" xlink:to="loc_scor_TemporaryEquityPercentageOfInterestHeld_019e64ea-08cd-72d4-b5ce-a89700796563" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_TemporaryEquityStockIssuedDuringPeriodSharesNewIssues_019e64ea-08cd-7bc1-a8ec-659fe56e7124" xlink:href="scor-20260630.xsd#scor_TemporaryEquityStockIssuedDuringPeriodSharesNewIssues"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_019e64ea-08cd-73b7-a496-1ac8e8ee0329" xlink:to="loc_scor_TemporaryEquityStockIssuedDuringPeriodSharesNewIssues_019e64ea-08cd-7bc1-a8ec-659fe56e7124" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DividendsPayableCurrentAndNoncurrent_019e64ea-08cd-72fc-8c2e-54c44d208f5d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DividendsPayableCurrentAndNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_019e64ea-08cd-73b7-a496-1ac8e8ee0329" xlink:to="loc_us-gaap_DividendsPayableCurrentAndNoncurrent_019e64ea-08cd-72fc-8c2e-54c44d208f5d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_TemporaryEquityDeferredDividendRatePercentage_019e64ea-08cd-7eea-8da5-df69825ccc40" xlink:href="scor-20260630.xsd#scor_TemporaryEquityDeferredDividendRatePercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_019e64ea-08cd-73b7-a496-1ac8e8ee0329" xlink:to="loc_scor_TemporaryEquityDeferredDividendRatePercentage_019e64ea-08cd-7eea-8da5-df69825ccc40" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_StockExchangeAgreementSharesExchanged_019e64ea-08cd-7d4c-b66e-1609f34e9d44" xlink:href="scor-20260630.xsd#scor_StockExchangeAgreementSharesExchanged"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_019e64ea-08cd-73b7-a496-1ac8e8ee0329" xlink:to="loc_scor_StockExchangeAgreementSharesExchanged_019e64ea-08cd-7d4c-b66e-1609f34e9d44" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_StockExchangeAgreementNewStockReceived_019e64ea-08cd-71ae-a9d5-0a0c62e6a44b" xlink:href="scor-20260630.xsd#scor_StockExchangeAgreementNewStockReceived"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_019e64ea-08cd-73b7-a496-1ac8e8ee0329" xlink:to="loc_scor_StockExchangeAgreementNewStockReceived_019e64ea-08cd-71ae-a9d5-0a0c62e6a44b" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_StockExchangeAgreementOneTimeCashPaymentToPreferredStockholders_019e64ea-08cd-759c-a37c-a30fa486cedf" xlink:href="scor-20260630.xsd#scor_StockExchangeAgreementOneTimeCashPaymentToPreferredStockholders"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_019e64ea-08cd-73b7-a496-1ac8e8ee0329" xlink:to="loc_scor_StockExchangeAgreementOneTimeCashPaymentToPreferredStockholders_019e64ea-08cd-759c-a37c-a30fa486cedf" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_PreferredStockRightToDesignateNumberOfDirectors_019e64ea-08cd-77d0-86b6-3d141adb3bf2" xlink:href="scor-20260630.xsd#scor_PreferredStockRightToDesignateNumberOfDirectors"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_019e64ea-08cd-73b7-a496-1ac8e8ee0329" xlink:to="loc_scor_PreferredStockRightToDesignateNumberOfDirectors_019e64ea-08cd-77d0-86b6-3d141adb3bf2" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_PreferredStockRightToDesignateNumberOfDirectorsDesignated_019e64ea-08cd-7669-a46b-2dbb5247df15" xlink:href="scor-20260630.xsd#scor_PreferredStockRightToDesignateNumberOfDirectorsDesignated"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_019e64ea-08cd-73b7-a496-1ac8e8ee0329" xlink:to="loc_scor_PreferredStockRightToDesignateNumberOfDirectorsDesignated_019e64ea-08cd-7669-a46b-2dbb5247df15" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TemporaryEquitySharesOutstanding_019e64ea-08cd-7581-9b36-d26346e9fa06" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TemporaryEquitySharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_019e64ea-08cd-73b7-a496-1ac8e8ee0329" xlink:to="loc_us-gaap_TemporaryEquitySharesOutstanding_019e64ea-08cd-7581-9b36-d26346e9fa06" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesOutstanding_019e64ea-08cd-721a-a17e-27046e4ec5e0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockSharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_019e64ea-08cd-73b7-a496-1ac8e8ee0329" xlink:to="loc_us-gaap_CommonStockSharesOutstanding_019e64ea-08cd-721a-a17e-27046e4ec5e0" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_StockExchangeAgreementOneTimeCashPaymentToPreferredStockholdersPresentValue_019e64ea-08cd-7192-ae67-9045c5e37971" xlink:href="scor-20260630.xsd#scor_StockExchangeAgreementOneTimeCashPaymentToPreferredStockholdersPresentValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_019e64ea-08cd-73b7-a496-1ac8e8ee0329" xlink:to="loc_scor_StockExchangeAgreementOneTimeCashPaymentToPreferredStockholdersPresentValue_019e64ea-08cd-7192-ae67-9045c5e37971" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermPurchaseCommitmentPeriod_019e64ea-08cd-70e4-8773-aa3586fed010" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermPurchaseCommitmentPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_019e64ea-08cd-73b7-a496-1ac8e8ee0329" xlink:to="loc_us-gaap_LongtermPurchaseCommitmentPeriod_019e64ea-08cd-70e4-8773-aa3586fed010" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionAmountsOfTransaction_019e64ea-08cd-7204-a470-0e17e69f005a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyTransactionAmountsOfTransaction"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_019e64ea-08cd-73b7-a496-1ac8e8ee0329" xlink:to="loc_us-gaap_RelatedPartyTransactionAmountsOfTransaction_019e64ea-08cd-7204-a470-0e17e69f005a" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_019e64ea-08cd-77ac-9b38-285a7090d642" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_019e64ea-08cd-73b7-a496-1ac8e8ee0329" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_019e64ea-08cd-77ac-9b38-285a7090d642" xlink:type="arc" order="14"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.comscore.com/role/RelatedPartyTransactionsScheduleofRelatedPartyTransactionswithRelatedPartiesDetails" xlink:type="simple" xlink:href="scor-20260630.xsd#RelatedPartyTransactionsScheduleofRelatedPartyTransactionswithRelatedPartiesDetails"/>
  <link:definitionLink xlink:role="http://www.comscore.com/role/RelatedPartyTransactionsScheduleofRelatedPartyTransactionswithRelatedPartiesDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionLineItems_019e64ea-08cd-7ba4-a161-59babfef8dad" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyTransactionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_019e64ea-08cd-7409-ac46-5d50a7a6185c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_019e64ea-08cd-7ba4-a161-59babfef8dad" xlink:to="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_019e64ea-08cd-7409-ac46-5d50a7a6185c" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019e64ea-08cd-78f0-ac14-313cafe5119a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_019e64ea-08cd-7409-ac46-5d50a7a6185c" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019e64ea-08cd-78f0-ac14-313cafe5119a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_019e64ea-08cd-78f0-ac14-313cafe5119a_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019e64ea-08cd-78f0-ac14-313cafe5119a" xlink:to="loc_us-gaap_RelatedPartyDomain_019e64ea-08cd-78f0-ac14-313cafe5119a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_019e64ea-08cd-7347-bbce-ba65cabbb17d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019e64ea-08cd-78f0-ac14-313cafe5119a" xlink:to="loc_us-gaap_RelatedPartyDomain_019e64ea-08cd-7347-bbce-ba65cabbb17d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyMember_019e64ea-08cd-798a-8fee-d727cfd2bb1d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_019e64ea-08cd-7347-bbce-ba65cabbb17d" xlink:to="loc_us-gaap_RelatedPartyMember_019e64ea-08cd-798a-8fee-d727cfd2bb1d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CounterpartyNameAxis_019e64ea-08cd-7dff-9527-bdf771402a9d" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_CounterpartyNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_019e64ea-08cd-7409-ac46-5d50a7a6185c" xlink:to="loc_srt_CounterpartyNameAxis_019e64ea-08cd-7dff-9527-bdf771402a9d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_019e64ea-08cd-7dff-9527-bdf771402a9d_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CounterpartyNameAxis_019e64ea-08cd-7dff-9527-bdf771402a9d" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_019e64ea-08cd-7dff-9527-bdf771402a9d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_019e64ea-08cd-7554-bbd4-3e7685dcbf03" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CounterpartyNameAxis_019e64ea-08cd-7dff-9527-bdf771402a9d" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_019e64ea-08cd-7554-bbd4-3e7685dcbf03" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_CharterCommunicationsHoldingCompanyLLCMember_019e64ea-08cd-7138-841f-157a9092880b" xlink:href="scor-20260630.xsd#scor_CharterCommunicationsHoldingCompanyLLCMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_019e64ea-08cd-7554-bbd4-3e7685dcbf03" xlink:to="loc_scor_CharterCommunicationsHoldingCompanyLLCMember_019e64ea-08cd-7138-841f-157a9092880b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_WPPplcMember_019e64ea-08cd-7625-a161-0c8d8376a68f" xlink:href="scor-20260630.xsd#scor_WPPplcMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_019e64ea-08cd-7554-bbd4-3e7685dcbf03" xlink:to="loc_scor_WPPplcMember_019e64ea-08cd-7625-a161-0c8d8376a68f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_019e64ea-08cd-72a5-a86e-f653512fd6da" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_019e64ea-08cd-7ba4-a161-59babfef8dad" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_019e64ea-08cd-72a5-a86e-f653512fd6da" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostOfGoodsAndServicesSold_019e64ea-08cd-764c-9887-c48d1797441b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CostOfGoodsAndServicesSold"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_019e64ea-08cd-7ba4-a161-59babfef8dad" xlink:to="loc_us-gaap_CostOfGoodsAndServicesSold_019e64ea-08cd-764c-9887-c48d1797441b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsAbstract_019e64ea-08cd-7c9a-a8dd-81e9233d1918" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetsAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_019e64ea-08cd-7ba4-a161-59babfef8dad" xlink:to="loc_us-gaap_AssetsAbstract_019e64ea-08cd-7c9a-a8dd-81e9233d1918" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsReceivableNetCurrent_019e64ea-08cd-7994-8ed4-9750d51026ed" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccountsReceivableNetCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_019e64ea-08cd-7c9a-a8dd-81e9233d1918" xlink:to="loc_us-gaap_AccountsReceivableNetCurrent_019e64ea-08cd-7994-8ed4-9750d51026ed" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesAbstract_019e64ea-08cd-7f63-a55b-847322e040a6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LiabilitiesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_019e64ea-08cd-7ba4-a161-59babfef8dad" xlink:to="loc_us-gaap_LiabilitiesAbstract_019e64ea-08cd-7f63-a55b-847322e040a6" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsPayableCurrent_019e64ea-08cd-7a7e-9b4f-c4444145456c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccountsPayableCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAbstract_019e64ea-08cd-7f63-a55b-847322e040a6" xlink:to="loc_us-gaap_AccountsPayableCurrent_019e64ea-08cd-7a7e-9b4f-c4444145456c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccruedLiabilitiesCurrent_019e64ea-08cd-7d84-9c20-1aa8f8f7a5b6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccruedLiabilitiesCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAbstract_019e64ea-08cd-7f63-a55b-847322e040a6" xlink:to="loc_us-gaap_AccruedLiabilitiesCurrent_019e64ea-08cd-7d84-9c20-1aa8f8f7a5b6" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerLiability_019e64ea-08cd-718c-a7c8-0a29a21274d9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ContractWithCustomerLiability"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAbstract_019e64ea-08cd-7f63-a55b-847322e040a6" xlink:to="loc_us-gaap_ContractWithCustomerLiability_019e64ea-08cd-718c-a7c8-0a29a21274d9" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_AccruedCostOfRevenuesNoncurrent_019e64ea-08cd-71c6-9c8f-f16e2636fd84" xlink:href="scor-20260630.xsd#scor_AccruedCostOfRevenuesNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAbstract_019e64ea-08cd-7f63-a55b-847322e040a6" xlink:to="loc_scor_AccruedCostOfRevenuesNoncurrent_019e64ea-08cd-71c6-9c8f-f16e2636fd84" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherLiabilitiesNoncurrent_019e64ea-08cd-7872-857e-0bf4abc5fb24" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherLiabilitiesNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAbstract_019e64ea-08cd-7f63-a55b-847322e040a6" xlink:to="loc_us-gaap_OtherLiabilitiesNoncurrent_019e64ea-08cd-7872-857e-0bf4abc5fb24" xlink:type="arc" order="5"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.comscore.com/role/CommitmentsandContingenciesNarrativeDetails" xlink:type="simple" xlink:href="scor-20260630.xsd#CommitmentsandContingenciesNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.comscore.com/role/CommitmentsandContingenciesNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingenciesLineItems_019e64ea-08cd-7380-ae8e-a1064c7699fe" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LossContingenciesLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingenciesTable_019e64ea-08cd-79cf-b596-9776a1889a9c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LossContingenciesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LossContingenciesLineItems_019e64ea-08cd-7380-ae8e-a1064c7699fe" xlink:to="loc_us-gaap_LossContingenciesTable_019e64ea-08cd-79cf-b596-9776a1889a9c" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_019e64ea-08cd-7670-af57-b1b8c1701f30" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LossContingenciesTable_019e64ea-08cd-79cf-b596-9776a1889a9c" xlink:to="loc_srt_RangeAxis_019e64ea-08cd-7670-af57-b1b8c1701f30" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_019e64ea-08cd-7670-af57-b1b8c1701f30_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_019e64ea-08cd-7670-af57-b1b8c1701f30" xlink:to="loc_srt_RangeMember_019e64ea-08cd-7670-af57-b1b8c1701f30_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_019e64ea-08cd-779e-a12d-dd4c9cc1f980" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_019e64ea-08cd-7670-af57-b1b8c1701f30" xlink:to="loc_srt_RangeMember_019e64ea-08cd-779e-a12d-dd4c9cc1f980" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_019e64ea-08cd-7aaf-8587-b7ed3242303c" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_019e64ea-08cd-779e-a12d-dd4c9cc1f980" xlink:to="loc_srt_MinimumMember_019e64ea-08cd-7aaf-8587-b7ed3242303c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_019e64ea-08cd-701e-b65e-beb6e140671e" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_019e64ea-08cd-779e-a12d-dd4c9cc1f980" xlink:to="loc_srt_MaximumMember_019e64ea-08cd-701e-b65e-beb6e140671e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_019e64ea-08cd-7010-b8e7-adbb9c38f431" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ProductOrServiceAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LossContingenciesTable_019e64ea-08cd-79cf-b596-9776a1889a9c" xlink:to="loc_srt_ProductOrServiceAxis_019e64ea-08cd-7010-b8e7-adbb9c38f431" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_019e64ea-08cd-7010-b8e7-adbb9c38f431_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_019e64ea-08cd-7010-b8e7-adbb9c38f431" xlink:to="loc_srt_ProductsAndServicesDomain_019e64ea-08cd-7010-b8e7-adbb9c38f431_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_019e64ea-08cd-727d-b9e5-7f622cf18672" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_019e64ea-08cd-7010-b8e7-adbb9c38f431" xlink:to="loc_srt_ProductsAndServicesDomain_019e64ea-08cd-727d-b9e5-7f622cf18672" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_SetTopBoxMember_019e64ea-08cd-768b-8913-ca6ebd9d4a4d" xlink:href="scor-20260630.xsd#scor_SetTopBoxMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_019e64ea-08cd-727d-b9e5-7f622cf18672" xlink:to="loc_scor_SetTopBoxMember_019e64ea-08cd-768b-8913-ca6ebd9d4a4d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_SmartTelevisionDataMember_019e64ea-08cd-7e3e-b314-b6da2e6232ca" xlink:href="scor-20260630.xsd#scor_SmartTelevisionDataMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_019e64ea-08cd-727d-b9e5-7f622cf18672" xlink:to="loc_scor_SmartTelevisionDataMember_019e64ea-08cd-7e3e-b314-b6da2e6232ca" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermPurchaseCommitmentPeriod_019e64ea-08cd-7fe7-be9d-5da553ad3c4a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermPurchaseCommitmentPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_019e64ea-08cd-7380-ae8e-a1064c7699fe" xlink:to="loc_us-gaap_LongtermPurchaseCommitmentPeriod_019e64ea-08cd-7fe7-be9d-5da553ad3c4a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PurchaseObligation_019e64ea-08cd-7326-bd40-796bf9a86ee4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PurchaseObligation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_019e64ea-08cd-7380-ae8e-a1064c7699fe" xlink:to="loc_us-gaap_PurchaseObligation_019e64ea-08cd-7326-bd40-796bf9a86ee4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractualObligation_019e64ea-08cd-73aa-a09f-dfaf696ce8be" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ContractualObligation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_019e64ea-08cd-7380-ae8e-a1064c7699fe" xlink:to="loc_us-gaap_ContractualObligation_019e64ea-08cd-73aa-a09f-dfaf696ce8be" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_ContractualObligationTerm_019e64ea-08cd-7478-80f3-fa35ba073b50" xlink:href="scor-20260630.xsd#scor_ContractualObligationTerm"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_019e64ea-08cd-7380-ae8e-a1064c7699fe" xlink:to="loc_scor_ContractualObligationTerm_019e64ea-08cd-7478-80f3-fa35ba073b50" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_SalesTaxAssessment_019e64ea-08cd-7e5f-825c-1ddf339ba94e" xlink:href="scor-20260630.xsd#scor_SalesTaxAssessment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_019e64ea-08cd-7380-ae8e-a1064c7699fe" xlink:to="loc_scor_SalesTaxAssessment_019e64ea-08cd-7e5f-825c-1ddf339ba94e" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingencyEstimateOfPossibleLoss_019fb2cc-93dd-714b-bea7-d01304b550a7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LossContingencyEstimateOfPossibleLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_019e64ea-08cd-7380-ae8e-a1064c7699fe" xlink:to="loc_us-gaap_LossContingencyEstimateOfPossibleLoss_019fb2cc-93dd-714b-bea7-d01304b550a7" xlink:type="arc" order="5"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.comscore.com/role/SegmentInformationScheduleofFinancialInformationthatisPresentedtotheCODMDetails" xlink:type="simple" xlink:href="scor-20260630.xsd#SegmentInformationScheduleofFinancialInformationthatisPresentedtotheCODMDetails"/>
  <link:definitionLink xlink:role="http://www.comscore.com/role/SegmentInformationScheduleofFinancialInformationthatisPresentedtotheCODMDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentReportingInformationLineItems_019e64ea-08cd-70ae-ac35-ba158ad0ca76" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentReportingInformationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_019e64ea-08cd-702f-82c9-1905f3ff5dcf" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019e64ea-08cd-70ae-ac35-ba158ad0ca76" xlink:to="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_019e64ea-08cd-702f-82c9-1905f3ff5dcf" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_019e64ea-08cd-7a93-a7aa-c662ee02ab8a" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ProductOrServiceAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_019e64ea-08cd-702f-82c9-1905f3ff5dcf" xlink:to="loc_srt_ProductOrServiceAxis_019e64ea-08cd-7a93-a7aa-c662ee02ab8a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_019e64ea-08cd-7a93-a7aa-c662ee02ab8a_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_019e64ea-08cd-7a93-a7aa-c662ee02ab8a" xlink:to="loc_srt_ProductsAndServicesDomain_019e64ea-08cd-7a93-a7aa-c662ee02ab8a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_019e64ea-08cd-71ff-bcf7-6603a4f8cc23" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_019e64ea-08cd-7a93-a7aa-c662ee02ab8a" xlink:to="loc_srt_ProductsAndServicesDomain_019e64ea-08cd-71ff-bcf7-6603a4f8cc23" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_ContentAdMeasurementMember_019e64ea-08cd-74fe-84da-1affb711bdb3" xlink:href="scor-20260630.xsd#scor_ContentAdMeasurementMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_019e64ea-08cd-71ff-bcf7-6603a4f8cc23" xlink:to="loc_scor_ContentAdMeasurementMember_019e64ea-08cd-74fe-84da-1affb711bdb3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_ContentAndAdMeasurementSyndicatedAudienceMember_019e64ea-08cd-7818-bfb8-33697b31947b" xlink:href="scor-20260630.xsd#scor_ContentAndAdMeasurementSyndicatedAudienceMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_019e64ea-08cd-71ff-bcf7-6603a4f8cc23" xlink:to="loc_scor_ContentAndAdMeasurementSyndicatedAudienceMember_019e64ea-08cd-7818-bfb8-33697b31947b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_ContentAndAdMeasurementCrossPlatformSolutionsMember_019e64ea-08cd-7c16-b355-0566adf0514c" xlink:href="scor-20260630.xsd#scor_ContentAndAdMeasurementCrossPlatformSolutionsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_019e64ea-08cd-71ff-bcf7-6603a4f8cc23" xlink:to="loc_scor_ContentAndAdMeasurementCrossPlatformSolutionsMember_019e64ea-08cd-7c16-b355-0566adf0514c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_ResearchInsightSolutionsMember_019e64ea-08cd-7aa8-891d-304d6070ffe7" xlink:href="scor-20260630.xsd#scor_ResearchInsightSolutionsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_019e64ea-08cd-71ff-bcf7-6603a4f8cc23" xlink:to="loc_scor_ResearchInsightSolutionsMember_019e64ea-08cd-7aa8-891d-304d6070ffe7" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_019e64ea-08cd-762b-94b3-1f6df0477417" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_019e64ea-08cd-702f-82c9-1905f3ff5dcf" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_019e64ea-08cd-762b-94b3-1f6df0477417" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_019e64ea-08cd-762b-94b3-1f6df0477417_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_019e64ea-08cd-762b-94b3-1f6df0477417" xlink:to="loc_us-gaap_SegmentDomain_019e64ea-08cd-762b-94b3-1f6df0477417_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_019e64ea-08cd-782a-88f9-8a3c4820d816" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_019e64ea-08cd-762b-94b3-1f6df0477417" xlink:to="loc_us-gaap_SegmentDomain_019e64ea-08cd-782a-88f9-8a3c4820d816" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_ReportableSegmentMember_019e64ea-08cd-7dee-b531-747b3b3f09cf" xlink:href="scor-20260630.xsd#scor_ReportableSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019e64ea-08cd-782a-88f9-8a3c4820d816" xlink:to="loc_scor_ReportableSegmentMember_019e64ea-08cd-7dee-b531-747b3b3f09cf" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_019e64ea-08cd-7042-a6d4-e366e9a32718" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019e64ea-08cd-70ae-ac35-ba158ad0ca76" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_019e64ea-08cd-7042-a6d4-e366e9a32718" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostOfGoodsAndServicesSold_019e64ea-08cd-75cf-a39d-7e0b12618497" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CostOfGoodsAndServicesSold"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019e64ea-08cd-70ae-ac35-ba158ad0ca76" xlink:to="loc_us-gaap_CostOfGoodsAndServicesSold_019e64ea-08cd-75cf-a39d-7e0b12618497" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CompensationExpenseExcludingCostOfGoodAndServiceSold_019e64ea-08cd-7f3a-b823-26a30b82eed3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CompensationExpenseExcludingCostOfGoodAndServiceSold"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019e64ea-08cd-70ae-ac35-ba158ad0ca76" xlink:to="loc_us-gaap_CompensationExpenseExcludingCostOfGoodAndServiceSold_019e64ea-08cd-7f3a-b823-26a30b82eed3" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProfessionalFees_019e64ea-08cd-7696-b259-f54810da0c32" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProfessionalFees"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019e64ea-08cd-70ae-ac35-ba158ad0ca76" xlink:to="loc_us-gaap_ProfessionalFees_019e64ea-08cd-7696-b259-f54810da0c32" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OccupancyNet_019e64ea-08cd-70f7-aade-129dada73d6e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OccupancyNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019e64ea-08cd-70ae-ac35-ba158ad0ca76" xlink:to="loc_us-gaap_OccupancyNet_019e64ea-08cd-70f7-aade-129dada73d6e" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_SoftwareLicensesMaintenanceAndSystems_019e64ea-08cd-733d-9b7c-6d1f3b48adfc" xlink:href="scor-20260630.xsd#scor_SoftwareLicensesMaintenanceAndSystems"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019e64ea-08cd-70ae-ac35-ba158ad0ca76" xlink:to="loc_scor_SoftwareLicensesMaintenanceAndSystems_019e64ea-08cd-733d-9b7c-6d1f3b48adfc" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TravelAndEntertainmentExpense_019e64ea-08cd-797b-b878-2aaf76e9a5c0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TravelAndEntertainmentExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019e64ea-08cd-70ae-ac35-ba158ad0ca76" xlink:to="loc_us-gaap_TravelAndEntertainmentExpense_019e64ea-08cd-797b-b878-2aaf76e9a5c0" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherCostAndExpenseOperating_019e64ea-08cd-7f77-a430-12cfbdb8a283" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherCostAndExpenseOperating"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019e64ea-08cd-70ae-ac35-ba158ad0ca76" xlink:to="loc_us-gaap_OtherCostAndExpenseOperating_019e64ea-08cd-7f77-a430-12cfbdb8a283" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingExpenses_019e64ea-08cd-799e-a0d6-a43cf00dcfad" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingExpenses"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019e64ea-08cd-70ae-ac35-ba158ad0ca76" xlink:to="loc_us-gaap_OperatingExpenses_019e64ea-08cd-799e-a0d6-a43cf00dcfad" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DepreciationDepletionAndAmortization_019e64ea-08cd-7e92-84f4-826fd28721e1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DepreciationDepletionAndAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019e64ea-08cd-70ae-ac35-ba158ad0ca76" xlink:to="loc_us-gaap_DepreciationDepletionAndAmortization_019e64ea-08cd-7e92-84f4-826fd28721e1" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllocatedShareBasedCompensationExpense_019e64ea-08cd-789f-bdd4-4700376b83d8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AllocatedShareBasedCompensationExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019e64ea-08cd-70ae-ac35-ba158ad0ca76" xlink:to="loc_us-gaap_AllocatedShareBasedCompensationExpense_019e64ea-08cd-789f-bdd4-4700376b83d8" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_TransformationCharges_019e64ea-08cd-76ed-b144-afb73b449c51" xlink:href="scor-20260630.xsd#scor_TransformationCharges"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019e64ea-08cd-70ae-ac35-ba158ad0ca76" xlink:to="loc_scor_TransformationCharges_019e64ea-08cd-76ed-b144-afb73b449c51" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_scor_StrategicTransactionCosts_019e64ea-08cd-7c55-abfb-2b2de3bf7ea0" xlink:href="scor-20260630.xsd#scor_StrategicTransactionCosts"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019e64ea-08cd-70ae-ac35-ba158ad0ca76" xlink:to="loc_scor_StrategicTransactionCosts_019e64ea-08cd-7c55-abfb-2b2de3bf7ea0" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ForeignCurrencyTransactionGainLossBeforeTax_019e64ea-08cd-71b7-94ce-6d76a030f771" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ForeignCurrencyTransactionGainLossBeforeTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019e64ea-08cd-70ae-ac35-ba158ad0ca76" xlink:to="loc_us-gaap_ForeignCurrencyTransactionGainLossBeforeTax_019e64ea-08cd-71b7-94ce-6d76a030f771" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestIncomeExpenseNonoperatingNet_019e64ea-08cd-74d5-a420-57fbabbd3d83" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestIncomeExpenseNonoperatingNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019e64ea-08cd-70ae-ac35-ba158ad0ca76" xlink:to="loc_us-gaap_InterestIncomeExpenseNonoperatingNet_019e64ea-08cd-74d5-a420-57fbabbd3d83" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxExpenseBenefit_019e64ea-08cd-7c50-a230-bb76f649434d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeTaxExpenseBenefit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019e64ea-08cd-70ae-ac35-ba158ad0ca76" xlink:to="loc_us-gaap_IncomeTaxExpenseBenefit_019e64ea-08cd-7c50-a230-bb76f649434d" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherNonoperatingIncomeExpense_019e64ea-08cd-7795-8a9c-040b0eae66ce" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherNonoperatingIncomeExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019e64ea-08cd-70ae-ac35-ba158ad0ca76" xlink:to="loc_us-gaap_OtherNonoperatingIncomeExpense_019e64ea-08cd-7795-8a9c-040b0eae66ce" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_019e64ea-08cd-7b10-a3f8-fd632be2a328" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019e64ea-08cd-70ae-ac35-ba158ad0ca76" xlink:to="loc_us-gaap_NetIncomeLoss_019e64ea-08cd-7b10-a3f8-fd632be2a328" xlink:type="arc" order="17"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.comscore.com/role/SubsequentEventsDetails" xlink:type="simple" xlink:href="scor-20260630.xsd#SubsequentEventsDetails"/>
  <link:definitionLink xlink:role="http://www.comscore.com/role/SubsequentEventsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventLineItems_019ff45c-29a7-7cf9-a0e9-7d7a68b6d4f3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTable_019ff45c-29a7-7aca-8039-19f4b41b3af2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SubsequentEventLineItems_019ff45c-29a7-7cf9-a0e9-7d7a68b6d4f3" xlink:to="loc_us-gaap_SubsequentEventTable_019ff45c-29a7-7aca-8039-19f4b41b3af2" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeAxis_019ff45e-8ea4-7847-bbfa-a2dd21ee33b5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_SubsequentEventTable_019ff45c-29a7-7aca-8039-19f4b41b3af2" xlink:to="loc_us-gaap_SubsequentEventTypeAxis_019ff45e-8ea4-7847-bbfa-a2dd21ee33b5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_019ff45e-8ea4-7847-bbfa-a2dd21ee33b5_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_019ff45e-8ea4-7847-bbfa-a2dd21ee33b5" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_019ff45e-8ea4-7847-bbfa-a2dd21ee33b5_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_019ff45e-8ea4-72df-a7e1-393145454c4d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_019ff45e-8ea4-7847-bbfa-a2dd21ee33b5" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_019ff45e-8ea4-72df-a7e1-393145454c4d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventMember_019ff45e-b593-7084-803b-bb59e87ce86d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventTypeDomain_019ff45e-8ea4-72df-a7e1-393145454c4d" xlink:to="loc_us-gaap_SubsequentEventMember_019ff45e-b593-7084-803b-bb59e87ce86d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_019ff45c-29a7-7184-9975-132a0236ae38" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_SubsequentEventTable_019ff45c-29a7-7aca-8039-19f4b41b3af2" xlink:to="loc_srt_RangeAxis_019ff45c-29a7-7184-9975-132a0236ae38" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_019ff45c-29a7-7184-9975-132a0236ae38_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_019ff45c-29a7-7184-9975-132a0236ae38" xlink:to="loc_srt_RangeMember_019ff45c-29a7-7184-9975-132a0236ae38_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_019ff45c-29a7-758b-ae7c-49f98ba108dc" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_019ff45c-29a7-7184-9975-132a0236ae38" xlink:to="loc_srt_RangeMember_019ff45c-29a7-758b-ae7c-49f98ba108dc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_019ff45c-642d-730d-a347-a619639cba51" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_019ff45c-29a7-758b-ae7c-49f98ba108dc" xlink:to="loc_srt_MinimumMember_019ff45c-642d-730d-a347-a619639cba51" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_019ff45c-5c4c-7e67-b6a2-3446ab11eb4f" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_019ff45c-29a7-758b-ae7c-49f98ba108dc" xlink:to="loc_srt_MaximumMember_019ff45c-5c4c-7e67-b6a2-3446ab11eb4f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringCostAndReserveAxis_019ff45c-6be7-7cfb-89f3-debcb2c0ecae" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RestructuringCostAndReserveAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_SubsequentEventTable_019ff45c-29a7-7aca-8039-19f4b41b3af2" xlink:to="loc_us-gaap_RestructuringCostAndReserveAxis_019ff45c-6be7-7cfb-89f3-debcb2c0ecae" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TypeOfRestructuringDomain_019ff45c-6be7-7cfb-89f3-debcb2c0ecae_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TypeOfRestructuringDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RestructuringCostAndReserveAxis_019ff45c-6be7-7cfb-89f3-debcb2c0ecae" xlink:to="loc_us-gaap_TypeOfRestructuringDomain_019ff45c-6be7-7cfb-89f3-debcb2c0ecae_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TypeOfRestructuringDomain_019ff45c-6be7-7b7e-ad7a-6ca9a03d999f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TypeOfRestructuringDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RestructuringCostAndReserveAxis_019ff45c-6be7-7cfb-89f3-debcb2c0ecae" xlink:to="loc_us-gaap_TypeOfRestructuringDomain_019ff45c-6be7-7b7e-ad7a-6ca9a03d999f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeSeveranceMember_019ff45c-78b2-74bb-a565-525e4ba8df4b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EmployeeSeveranceMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TypeOfRestructuringDomain_019ff45c-6be7-7b7e-ad7a-6ca9a03d999f" xlink:to="loc_us-gaap_EmployeeSeveranceMember_019ff45c-78b2-74bb-a565-525e4ba8df4b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractTerminationMember_019ff45c-7f49-7ea0-b57c-cfd86e00340f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ContractTerminationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TypeOfRestructuringDomain_019ff45c-6be7-7b7e-ad7a-6ca9a03d999f" xlink:to="loc_us-gaap_ContractTerminationMember_019ff45c-7f49-7ea0-b57c-cfd86e00340f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherRestructuringMember_019ff45c-83f5-7b99-8b70-15f9b0473e2b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherRestructuringMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TypeOfRestructuringDomain_019ff45c-6be7-7b7e-ad7a-6ca9a03d999f" xlink:to="loc_us-gaap_OtherRestructuringMember_019ff45c-83f5-7b99-8b70-15f9b0473e2b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringAndRelatedCostExpectedCost1_019ff45c-29a7-79a9-8322-6a2357ddb773" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RestructuringAndRelatedCostExpectedCost1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_019ff45c-29a7-7cf9-a0e9-7d7a68b6d4f3" xlink:to="loc_us-gaap_RestructuringAndRelatedCostExpectedCost1_019ff45c-29a7-79a9-8322-6a2357ddb773" xlink:type="arc" order="0"/>
  </link:definitionLink>
</link:linkbase>
