The Collaborative International Dictionary of English v.0.48:

Petitory \Pet"i*to*ry\, a. [L. petitorius, fr. petere, petitum,
   to beg, ask: cf. F. p['e]titore.]
   Petitioning; soliciting; supplicating. --Sir W. Hamilton.
   [1913 Webster]

   Petitory suit or Petitory action (Admiralty Law), a suit
      in which the mere title to property is litigated and
      sought to be enforced, as distinguished from a possessory
      suit; also (Scots Law), a suit wherein the plaintiff
      claims something as due him by the defendant. --Burrill.
      [1913 Webster]

Bouvier's Law Dictionary, Revised 6th Ed (1856):

PETITORY. That which demands or petitions that which has, the, quality of a
prayer or petition; a right to demand.
     2. A petitory suit or action is understood to be one in which the mere
title to property is to be enforced by means of a demand or petition, as
distinguished from a possessory suit. 1 Kent, Com. 371.
     3. In the Scotch law, petitory actions are so called, not because
something is sought to be awarded by the judge, for in that sense all
actions must be petitory, but because some demand is made upon the defender,
in consequence either of the right of property or credit in the pursuer.
Thus, actions for restitution of movables, actions of pounding, of
forthcoming, and indeed all personal actions upon contracts, or quasi
contracts, which the Romans called condictiones, are petitory. Ersk. Inst.
b. 4, t. 1, n. 47.