Also found in: Dictionary, Thesaurus, Encyclopedia, Wikipedia. counterpart n. in the law of contracts, a written paper which is one of several documents which constitute a contract, such as a written offer and a written acceptance.

counterpart n. in the law of contracts, a written paper which is one of several documents which constitute a contract, such as a written offer and a written acceptance. Often a contract is in several counterparts which are the same but each paper is signed by a different party, particularly if they are in different localities.

In the law, a counterpart is a duplicate document. The term "counterpart" is used in legal documents to describe a copy of a contract that is signed and is considered legally binding, in the same way as the original.

The term counterpart has its roots in medieval English law, referring to one of two corresponding copies of a legal document, each of which was signed and kept by a party to the agreement. The word "counterpart" derives from the Latin "contra partes," meaning "against the parties."