What is the term for a written document that can be presented as evidence in a legal proceeding?

The term for a written document that can be presented as evidence in a legal proceeding is "instrument." In legal terminology, an instrument refers to any formal document, such as a contract, deed, or agreement, that acts as evidence of a certain legal transaction or relationship. Instruments are pivotal in establishing rights and obligations between parties and are often used in court to substantiate claims.

While affidavits, depositions, and complaints are also important legal documents, they serve more specific purposes. An affidavit is a sworn statement made under oath, used to provide evidence in written form. A deposition is a process where witnesses provide sworn testimony outside of court, and this testimony is recorded for later use in legal proceedings. A complaint is a formal legal document that initiates a lawsuit, outlining the plaintiff's claims against the defendant. Thus, "instrument" is the most accurate term encompassing any written document meant to serve as evidence in legal contexts.