<?xml version="1.0" encoding="US-ASCII" standalone="no"?>
    <!-- Field: Doc-Info; Name: Generator; Value: GoFiler Complete; Version: 6.5a -->
    <!-- Field: Doc-Info; Name: VendorURI; Value: https://www.novaworks.com -->
    <!-- Field: Doc-Info; Name: Status; Value: 0x00000000 -->
<link:linkbase xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" xmlns:xbrli="http://www.xbrl.org/2003/instance" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd">
    <link:roleRef xlink:type="simple" xlink:href="spexu-20260331.xsd#Cover" roleURI="http://spectreacquisitioncorp.com/role/Cover" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/spac/2025q3/spac-2025q3.xsd#SponsorsAffiliatesOrPromotersOnly" roleURI="http://xbrl.sec.gov/spac/role/SponsorsAffiliateOrPromotersOnly" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/spac/2025q3/spac-2025q3.xsd#CompensationNaturesOnly" roleURI="http://xbrl.sec.gov/spac/role/CompensationNaturesOnly" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/spac/2025q3/spac-2025q3.xsd#SecurityClassesOnly" roleURI="http://xbrl.sec.gov/spac/role/SecurityClassesOnly" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/spac/2025q3/spac-2025q3.xsd#RedemptionLevelsOnly" roleURI="http://xbrl.sec.gov/spac/role/RedemptionLevelsOnly" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/spac/2025q3/spac-2025q3.xsd#OverAllotmentOptionsOnly" roleURI="http://xbrl.sec.gov/spac/role/OverAllotmentOptionsOnly" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/spac/2025q3/spac-2025q3.xsd#DilutionSourcesOnly" roleURI="http://xbrl.sec.gov/spac/role/DilutionSourcesOnly" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/spac/2025q3/spac-2025q3.xsd#ControllingPersonsOnly" roleURI="http://xbrl.sec.gov/spac/role/ControllingPersonsOnly" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/spac/2025q3/spac-2025q3.xsd#DirectAndIndirectMaterialInterestHoldersOnly" roleURI="http://xbrl.sec.gov/spac/role/DirectAndIndirectMaterialInterestHoldersOnly" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/spac/2025q3/spac-2025q3.xsd#ConflictOfInterestPartiesOnly" roleURI="http://xbrl.sec.gov/spac/role/ConflictOfInterestPartiesOnly" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/spac/2025q3/spac-2025q3.xsd#OfficersAndDirectorsOnly" roleURI="http://xbrl.sec.gov/spac/role/OfficersAndDirectorsOnly" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/spac/2025q3/spac-2025q3.xsd#DeSpacAffectedPartiesOnly" roleURI="http://xbrl.sec.gov/spac/role/DeSpacAffectedPartiesOnly" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/spac/2025q3/spac-2025q3.xsd#MaterialFinancingTransactionsOnly" roleURI="http://xbrl.sec.gov/spac/role/MaterialFinancingTransactionsOnly" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/spac/2025q3/spac-2025q3.xsd#OutsidePartyOrUnaffiliatedRepresentativeDocumentsOnly" roleURI="http://xbrl.sec.gov/spac/role/OutsidePartyOrUnaffiliatedRepresentativeDocumentsOnly" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/spac/2025q3/spac-2025q3.xsd#DeSpacProjectionPreparersOnly" roleURI="http://xbrl.sec.gov/spac/role/DeSpacProjectionPreparersOnly" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/spac/2025q3/spac-2025q3.xsd#DeSpacProjectionScenariosOnly" roleURI="http://xbrl.sec.gov/spac/role/DeSpacProjectionScenariosOnly" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/spac/2025q3/spac-2025q3.xsd#RangeOnly" roleURI="http://xbrl.sec.gov/spac/role/RangeOnly" />
    <link:arcroleRef xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#hypercube-dimension" arcroleURI="http://xbrl.org/int/dim/arcrole/hypercube-dimension" />
    <link:arcroleRef xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-domain" arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-domain" />
    <link:arcroleRef xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#domain-member" arcroleURI="http://xbrl.org/int/dim/arcrole/domain-member" />
    <link:arcroleRef xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#all" arcroleURI="http://xbrl.org/int/dim/arcrole/all" />
    <link:arcroleRef xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#notAll" arcroleURI="http://xbrl.org/int/dim/arcrole/notAll" />
    <link:arcroleRef xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-default" arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-default" />
    <link:definitionLink xlink:type="extended" xlink:role="http://spectreacquisitioncorp.com/role/Cover" xlink:title="00000001 - Document - Cover" />
    <link:definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/spac/role/SponsorsAffiliateOrPromotersOnly">
      <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/spac/2025q3/spac-2025q3.xsd#spac_AllSpacSponsorsAffiliatesOrPromotersMember" xlink:label="loc_spacAllSpacSponsorsAffiliatesOrPromotersMember" />
      <link:loc xlink:type="locator" xlink:href="spexu-20260331.xsd#SPEXU_InsiderSharesMember" xlink:label="loc_SPEXUInsiderSharesMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_spacAllSpacSponsorsAffiliatesOrPromotersMember" xlink:to="loc_SPEXUInsiderSharesMember" xlink:type="arc" order="0" />
      <link:loc xlink:type="locator" xlink:href="spexu-20260331.xsd#SPEXU_SponsorOfficersAndDirectorsMember" xlink:label="loc_SPEXUSponsorOfficersAndDirectorsMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_spacAllSpacSponsorsAffiliatesOrPromotersMember" xlink:to="loc_SPEXUSponsorOfficersAndDirectorsMember" xlink:type="arc" order="10" />
      <link:loc xlink:type="locator" xlink:href="spexu-20260331.xsd#SPEXU_SpectreRHLimitedOfficersAndDirectorsMember" xlink:label="loc_SPEXUSpectreRHLimitedOfficersAndDirectorsMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_spacAllSpacSponsorsAffiliatesOrPromotersMember" xlink:to="loc_SPEXUSpectreRHLimitedOfficersAndDirectorsMember" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="spexu-20260331.xsd#SPEXU_SpectreRHLimitedMember" xlink:label="loc_SPEXUSpectreRHLimitedMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_spacAllSpacSponsorsAffiliatesOrPromotersMember" xlink:to="loc_SPEXUSpectreRHLimitedMember" xlink:type="arc" order="30" />
    </link:definitionLink>
    <link:definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/spac/role/CompensationNaturesOnly">
      <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/spac/2025q3/spac-2025q3.xsd#spac_AllCompensationNaturesMember" xlink:label="loc_spacAllCompensationNaturesMember" />
      <link:loc xlink:type="locator" xlink:href="spexu-20260331.xsd#SPEXU_InsiderSharesMember" xlink:label="loc_SPEXUInsiderSharesMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_spacAllCompensationNaturesMember" xlink:to="loc_SPEXUInsiderSharesMember" xlink:type="arc" order="0" />
      <link:loc xlink:type="locator" xlink:href="spexu-20260331.xsd#SPEXU_PrivateUnitsMember" xlink:label="loc_SPEXUPrivateUnitsMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_spacAllCompensationNaturesMember" xlink:to="loc_SPEXUPrivateUnitsMember" xlink:type="arc" order="10" />
      <link:loc xlink:type="locator" xlink:href="spexu-20260331.xsd#SPEXU_UnderwritersOverAllotmentOptionMember" xlink:label="loc_SPEXUUnderwritersOverAllotmentOptionMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_spacAllCompensationNaturesMember" xlink:to="loc_SPEXUUnderwritersOverAllotmentOptionMember" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="spexu-20260331.xsd#SPEXU_PrivatePlacementWarrantsMember" xlink:label="loc_SPEXUPrivatePlacementWarrantsMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_spacAllCompensationNaturesMember" xlink:to="loc_SPEXUPrivatePlacementWarrantsMember" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="spexu-20260331.xsd#SPEXU_LoanMember" xlink:label="loc_SPEXULoanMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_spacAllCompensationNaturesMember" xlink:to="loc_SPEXULoanMember" xlink:type="arc" order="40" />
    </link:definitionLink>
    <link:definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/spac/role/SecurityClassesOnly">
      <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/spac/2025q3/spac-2025q3.xsd#spac_AllSecurityClassesMember" xlink:label="loc_spacAllSecurityClassesMember" />
      <link:loc xlink:type="locator" xlink:href="spexu-20260331.xsd#SPEXU_OfferingPriceOf10.00PerUnitMember" xlink:label="loc_SPEXUOfferingPriceOf10.00PerUnitMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_spacAllSecurityClassesMember" xlink:to="loc_SPEXUOfferingPriceOf10.00PerUnitMember" xlink:type="arc" order="0" />
      <link:loc xlink:type="locator" xlink:href="spexu-20260331.xsd#SPEXU_DifferenceBetweenNTBVAndOfferingPriceMember" xlink:label="loc_SPEXUDifferenceBetweenNTBVAndOfferingPriceMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_spacAllSecurityClassesMember" xlink:to="loc_SPEXUDifferenceBetweenNTBVAndOfferingPriceMember" xlink:type="arc" order="10" />
      <link:loc xlink:type="locator" xlink:href="spexu-20260331.xsd#SPEXU_FullOverAllotmentMember" xlink:label="loc_SPEXUFullOverAllotmentMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_spacAllSecurityClassesMember" xlink:to="loc_SPEXUFullOverAllotmentMember" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="spexu-20260331.xsd#SPEXU_NoOverAllotmentMember" xlink:label="loc_SPEXUNoOverAllotmentMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_spacAllSecurityClassesMember" xlink:to="loc_SPEXUNoOverAllotmentMember" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="spexu-20260331.xsd#SPEXU_InsiderSharesMember" xlink:label="loc_SPEXUInsiderSharesMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_spacAllSecurityClassesMember" xlink:to="loc_SPEXUInsiderSharesMember" xlink:type="arc" order="40" />
      <link:loc xlink:type="locator" xlink:href="spexu-20260331.xsd#SPEXU_PrivateUnitsMember" xlink:label="loc_SPEXUPrivateUnitsMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_spacAllSecurityClassesMember" xlink:to="loc_SPEXUPrivateUnitsMember" xlink:type="arc" order="50" />
    </link:definitionLink>
    <link:definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/spac/role/RedemptionLevelsOnly" />
    <link:definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/spac/role/OverAllotmentOptionsOnly" />
    <link:definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/spac/role/DilutionSourcesOnly">
      <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/spac/2025q3/spac-2025q3.xsd#spac_AllDilutionSourcesMember" xlink:label="loc_spacAllDilutionSourcesMember" />
      <link:loc xlink:type="locator" xlink:href="spexu-20260331.xsd#SPEXU_NetProceedsFromThisOfferingAndTheSaleOfPrivateUnitsMember" xlink:label="loc_SPEXUNetProceedsFromThisOfferingAndTheSaleOfPrivateUnitsMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_spacAllDilutionSourcesMember" xlink:to="loc_SPEXUNetProceedsFromThisOfferingAndTheSaleOfPrivateUnitsMember" xlink:type="arc" order="0" />
      <link:loc xlink:type="locator" xlink:href="spexu-20260331.xsd#SPEXU_OfferingCostsAccruedForAndPaidInAdvanceExcludedFromTangibleBookValueMember" xlink:label="loc_SPEXUOfferingCostsAccruedForAndPaidInAdvanceExcludedFromTangibleBookValueMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_spacAllDilutionSourcesMember" xlink:to="loc_SPEXUOfferingCostsAccruedForAndPaidInAdvanceExcludedFromTangibleBookValueMember" xlink:type="arc" order="10" />
      <link:loc xlink:type="locator" xlink:href="spexu-20260331.xsd#SPEXU_ProceedsSubjectToRedemptionMember" xlink:label="loc_SPEXUProceedsSubjectToRedemptionMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_spacAllDilutionSourcesMember" xlink:to="loc_SPEXUProceedsSubjectToRedemptionMember" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="spexu-20260331.xsd#SPEXU_OrdinarySharesIssuedAndOutstandingPriorToThisOfferingMember" xlink:label="loc_SPEXUOrdinarySharesIssuedAndOutstandingPriorToThisOfferingMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_spacAllDilutionSourcesMember" xlink:to="loc_SPEXUOrdinarySharesIssuedAndOutstandingPriorToThisOfferingMember" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="spexu-20260331.xsd#SPEXU_OrdinarySharesIncludedInPublicUnitsOfferedMember" xlink:label="loc_SPEXUOrdinarySharesIncludedInPublicUnitsOfferedMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_spacAllDilutionSourcesMember" xlink:to="loc_SPEXUOrdinarySharesIncludedInPublicUnitsOfferedMember" xlink:type="arc" order="40" />
      <link:loc xlink:type="locator" xlink:href="spexu-20260331.xsd#SPEXU_OrdinarySharesIncludedInPrivateUnitsMember" xlink:label="loc_SPEXUOrdinarySharesIncludedInPrivateUnitsMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_spacAllDilutionSourcesMember" xlink:to="loc_SPEXUOrdinarySharesIncludedInPrivateUnitsMember" xlink:type="arc" order="50" />
      <link:loc xlink:type="locator" xlink:href="spexu-20260331.xsd#SPEXU_OrdinarySharesSubjectToRedemptionMember" xlink:label="loc_SPEXUOrdinarySharesSubjectToRedemptionMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_spacAllDilutionSourcesMember" xlink:to="loc_SPEXUOrdinarySharesSubjectToRedemptionMember" xlink:type="arc" order="60" />
    </link:definitionLink>
    <link:definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/spac/role/ControllingPersonsOnly" />
    <link:definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/spac/role/DirectAndIndirectMaterialInterestHoldersOnly" />
    <link:definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/spac/role/ConflictOfInterestPartiesOnly" />
    <link:definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/spac/role/OfficersAndDirectorsOnly" />
    <link:definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/spac/role/DeSpacAffectedPartiesOnly" />
    <link:definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/spac/role/MaterialFinancingTransactionsOnly" />
    <link:definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/spac/role/OutsidePartyOrUnaffiliatedRepresentativeDocumentsOnly" />
    <link:definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/spac/role/DeSpacProjectionPreparersOnly" />
    <link:definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/spac/role/DeSpacProjectionScenariosOnly" />
    <link:definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/spac/role/RangeOnly" />
</link:linkbase>
