The Collaborative International Dictionary of English v.0.48:

Prior \Pri"or\, n. [OE. priour, OF. priour, prior, priur, F.
   prieur, from L. prior former, superior. See Prior, a.]
   1. (Eccl.) The superior of a priory, and next below an abbot
      in dignity.
      [1913 Webster]

   2. a chief magistrate, as in the republic of Florence in the
      middle ages. --[RHUD]
      [PJC]

   Conventical prior, or Conventual prior, a prior who is at
      the head of his own house. See the Note under Priory.

   Claustral prior, an official next in rank to the abbot in a
      monastery; prior of the cloisters.
      [1913 Webster]