Deposition, in law, the testimony of a witness reduced to writing in due form of law, taken by virtue of a commission or other authority of a competent tribunal. When taken by commission, depositions are usually in answer to questions upon the examination in chief, and upon cross-examination, prepared and submitted to the court from which the commission issues. In other cases they are taken by consent of counsel or in due course of law, the privilege of cross-examination being always preserved, except in some cases where depositions of matters within the knowledge of persons of great age are allowed to be taken for the purpose of perpetuating their testimony, and in cases where immediate death by violence is expected. This must, when possible, be sworn to and signed by the witness. In the United States, compulsory process is usually allowed to procure this evidence. - In ecclesiastical law, deposition is the act of depriving a clergyman by a competent tribunal of his clerical orders, in punishment of some offence, and to prevent his acting in his clerical character.