The term that describes a court order directing a jailer to keep a person in custody until a further order is issued is known as a mittimus. A mittimus typically serves as a legal document that authorizes the detention of an individual in a correctional facility. It reflects the court's directive for the jailer to hold that person, ensuring their custody following a judicial decision, like a conviction or sentencing. Conversely, the other terms have distinct meanings in legal terminology. A writ generally refers to any formal written order issued by a body with administrative or legal jurisdiction. Habeas corpus is a legal principle that safeguards an individual's right to be free from unlawful detention, allowing a person to challenge the legality of their imprisonment. A subpoena is a command to appear at a legal proceeding or produce evidence; it does not pertain to a direct custody order. Each of these terms plays a significant role in the legal system, but mittimus specifically addresses the aspect of directing custody within corrections.