In law and in religion, testimony is a solemn attestation as to the truth of a matter. The words "testimony" and "testify" both derive from the Latin word testis, referring to the notion of a disinterested third-party witness.
In the law, testimony is a form of evidence given by a witness who makes a solemn statement or declaration of fact. Testimony may be spoken or written. It is usually made by oath or affirmation under penalty of perjury.