#opposite_number__counterpart__vis-a-vis  a person or thing having the same function or characteristics as another
  supertype:  equivalent  a person or thing equal to another in value or measure or force or effect or significance etc: "send two dollars or the equivalent in stamps"
  subtype:  match.opposite_number  something that resembles or harmonizes with; "that tie makes a good match with your jacket"
  subtype:  complement.opposite_number  either of two parts that mutually complete each other

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