The Collaborative International Dictionary of English v.0.48:

Conciliate \Con*cil"i*ate\ (?; 106), v. t. [imp. & p. p.
   Conciliated; p. pr & vb. n. Conciliating.] [L.
   conciliatus, p. p. of conciliare to draw or bring together,
   unite, from concilium council. See Council.]
   To win ower; to gain from a state of hostility; to gain the
   good will or favor of; to make friendly; to mollify; to
   propitiate; to appease.
   [1913 Webster]

         The rapacity of his father's administration had excited
         such universal discontent, that it was found expedient
         to conciliate the nation.                --Hallam.

   Syn: To reconcile; propitiate; appease; pacify.
        [1913 Webster]

WordNet (r) 3.0 (2006):

conciliate
    v 1: cause to be more favorably inclined; gain the good will of;
         "She managed to mollify the angry customer" [syn: pacify,
         lenify, conciliate, assuage, appease, mollify,
         placate, gentle, gruntle]
    2: come to terms; "After some discussion we finally made up"
       [syn: reconcile, patch up, make up, conciliate,
       settle]
    3: make (one thing) compatible with (another); "The scientists
       had to accommodate the new results with the existing
       theories" [syn: accommodate, reconcile, conciliate]

Moby Thesaurus II by Grady Ward, 1.0:

18 Moby Thesaurus words for "conciliate":
   allay, appease, calm, cool, defuse, dulcify, lay, lay the dust,
   mollify, pacify, placate, pour balm on, propitiate, smooth,
   smooth down, smooth over, soothe, tranquilize