PRIOR is a 5 letter word that starts with P.

1.    Then the old man Was wroth, and doubled up his hands.
                                                  --Tennyson.
   
   3. To be the double of; to exceed by twofold; to contain or
      be worth twice as much as.
   
            Thus re["e]nforced, against the adverse fleet, Still
            doubling ours, brave Rupert leads the way. --Dryden.
   
   4. To pass around or by; to march or sail round, so as to
      reverse the direction of motion.
   
            Sailing along the coast, the doubled the promontory
            of Carthage.                          --Knolles.
   
   5. (Mil.) To unite, as ranks or files, so as to form one from
      each two.
   
   

2. \Pri"or\, a.
   First, precedent, or superior in the order of cognition,
   reason or generality, origin, development, rank, etc.
   
   

3. \Pri"or\, a. [L. prior former, previous, better, superior;
   compar. corresponding to primus first, and pro for. See
   {Former}, and cf. {Prime}, a., and {Pre-}, {Pro-}.]
   Preceding in the order of time; former; antecedent; anterior;
   previous; as, a prior discovery; prior obligation; -- used
   elliptically in cases like the following: he lived alone [in
   the time] prior to his marriage.
   
   

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