Meaning

noun a person or thing having the same function or characteristics as another

noun a duplicate copy

originFrom Middle English conterpart, countre parte (“duplicate of a legal document”), equivalent to counter- + part. Compare Old French contrepartie, itself from contre (“facing, opposite”) (from Latin contra (“against”)) + partie (“copy of a person or thing”) (originally past participle of partīre (“to divide”)).

Etymology from Wiktionary, CC BY-SA 3.0