noun, verb
noun (law) a written order to attend a court of law as a WITNESS to give evidence:
He was served with a subpoena. * She is appearing today under subpoena (= she has been given a subpoena to appear).
verb (law) to order sb to attend a court of law and give evidence as a WITNESS: [VNtoinf] The court subpoenaed her to appear as a witness. [also VN]