Source : Webster's Revised Unabridged Dictionary (1913)

Intercessor \In`ter*ces"sor\, n. [L., a surety: cf. F.
   intercesseur.]
   1. One who goes between, or intercedes; a mediator.
      (a) One who interposes between parties at variance, with a
          view to reconcile them.
      (b) One who pleads in behalf of another. --Milton.

   2. (Eccl.) A bishop, who, during a vacancy of the see,
      administers the bishopric till a successor is installed.

Source : WordNet®

intercessor
     n : a negotiator who acts as a link between parties [syn: {mediator},
          {go-between}, {intermediator}, {intermediary}]