counterpart
Synonym discussion
Sense: noun/1
These four words all describe someone or something that matches another, but they differ in scope and register. 'Counterpart' is the most specific: it means a person or thing with the same function in a different setting — for instance, the US Secretary of State and her Chinese counterpart. 'Equivalent' is broader: it can refer to value ('an equivalent amount'), meaning, or status without requiring the same role in a different organization. 'Opposite number' is an informal British expression with the same meaning as 'counterpart' ('my opposite number at the Paris office'). 'Peer' emphasises equal rank rather than matching function, and is commonly used within the same organisation ('she was respected by her peers'). For organisational role-matching, 'counterpart' is the most precise choice.
Common collocations
Etymology
From French 'contrepartie', meaning a duplicate or matching copy, formed from 'contre-' (against, opposite) and 'partie' (part, share). The word originally referred to a duplicate legal document; in the 1800s it broadened to describe a person or thing that corresponds to another in role or function.