The Collaborative International Dictionary of English v.0.48:

Intercede \In`ter*cede"\, v. i. [imp. & p. p. Interceded; p.
   pr. & vb. n. Interceding.] [L. intercedere, intercessum;
   inter between + cedere to pass: cf. F. interc['e]der. See
   Cede.]
   [1913 Webster]
   1. To pass between; to intervene. [Obs.]
      [1913 Webster]

            He supposed that a vast period interceded between
            that origination and the age wherein he lived. --Sir
                                                  M. Hale.
      [1913 Webster]

   2. To act between parties with a view to reconcile
      differences; to make intercession; to beg or plead in
      behalf of another; to mediate; -- usually followed by with
      and for or on behalf of; as, I will intercede with him for
      you.
      [1913 Webster]

            I to the lords will intercede, not doubting
            Their favorable ear.                  --Milton.

   Syn: To mediate; arbitrate. See Interpose.
        [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Intercede \In`ter*cede"\, v. t.
   To be, to come, or to pass, between; to separate. [Obs.]
   --Sir I. Newton.
   [1913 Webster]

WordNet (r) 3.0 (2006):

intercede
    v 1: act between parties with a view to reconciling differences;
         "He interceded in the family dispute"; "He mediated a
         settlement" [syn: intercede, mediate, intermediate,
         liaise, arbitrate]

Moby Thesaurus II by Grady Ward, 1.0:

19 Moby Thesaurus words for "intercede":
   act between, arbitrate, bargain, go between, interfere,
   intermediate, interpose, intervene, judge, make terms, mediate,
   meet halfway, moderate, negotiate, referee, represent, step in,
   treat with, umpire