Subpoena

Strafbewehrte Vorladung als Zeuge - subpoena ad testificandum, commonly called the subpoena, to attend the court as a witness.
==Subpoena as generally defined in the United States==
The obligation of the individual to attend the court as a witness is enforced by a process of the court, particular process being the subpoena ad testificandum, commonly called the subpoena in the United States. This writ, or form, commands the witness, under penalty, to appear at a trial to give testimony. 
In order for the power of the court to compel the appearance and testimony of a witness in United States Federal Courts, or in various state courts, the person who is sought must be served with a subpoena.U. S. v. Blanton, 534 F. Supp. 295 (S.D. Fla. 1982)
The subpoena is a process in the name of the court or a judge, carrying with it a command dignified by the sanction of the law.[32]
A subpoena has been called a mandate lawfully issued under the seal of the court by a clerk thereof.
=== www===
* Subpoena_as_generally_defined
* https://de.wikipedia.org/wiki/Ladung_(Recht)