Subpoena ad testificandum
Black's Law Dictionary · Henry Campbell Black, M.A. · 1910
Black's Law Dictionary
Subpoena to testify. The common subpoena requiring the attendance of a witness on a trial, inquisition, or examination.
3 Bl. Comm. 369; In re Strauss, 30 App. Div. 610, 52 1ST. Y. Supp. 392,