The Collaborative International Dictionary of English v.0.48:
Provost \Prov"ost\, n. [OF. provost (L. prae and pro being
confused), F. prev[^o]t, fr. L. praepositus placed before, a
chief, fr. praeponere to place before: cf. AS. pr[=a]fost,
pr[=o]fast. See Preposition, and cf. Propound.]
1. A person who is appointed to superintend, or preside over,
something; the chief magistrate in some cities and towns;
as, the provost of Edinburgh or of Glasgow, answering to
the mayor of other cities; the provost of a college,
answering to president; the provost or head of certain
2. 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
(b) (Nav.) An officer who has charge of prisoners on trial
by court-martial, serves notices to witnesses, etc.
WordNet (r) 3.0 (2006):
n 1: the supervisor of the military police