What does "provost" mean?

Provost: The keeper of a prison. [Obs.] Shak. Note: In France, formerly, a provost was an inferior judge who had cognizance of civil causes. The grand provost of France, or of the household, had jurisdiction in the king's house, and over its officers. Provost marshal (often pronounced . (a) (Mil.) An officer appointed in every army, in the field, to secure the prisoners confined on charges of a general nature. He also performs such other duties pertaining to police and discipline as the regulations of the service or the commander's orders impose upon him. (b) (Nav.) An officer who has charge of prisoners on trial by court-martial, serves notices to witnesses, etc.