What is a written court order that compels a witness to appear in court?

The term that refers to a written court order compelling a witness to appear in court is a subpoena. A subpoena is a crucial legal instrument used to ensure that individuals contribute to the judicial process, whether by providing testimony or producing documents relevant to a case. It serves to uphold the integrity of the legal system by making sure that all pertinent information is presented during legal proceedings.

The other options pertain to different legal concepts. A writ is a formal order issued by a court, which can take various forms depending on its purpose, such as ordering the performance of a specific act. A summons is generally used to notify a defendant of legal action against them and to summon them to court, but it does not specifically compel a witness to appear. A mandate typically refers to an authoritative command or instruction, and in legal contexts, it often pertains to the direction given by an appellate court to a lower court. However, none of these terms replace the specific function of a subpoena in the context of compelling witness appearance.