The Collaborative International Dictionary of English v.0.48:

Vindication \Vin`di*ca"tion\, n. [L. vindicatio a laying claim,
   defense, vindication. See Vindicate.]
   1. The act of vindicating, or the state of being vindicated;
      defense; justification against denial or censure; as, the
      vindication of opinions; his vindication is complete.
      [1913 Webster]

            Occasion for the vindication of this passage in my
            book.                                 --Locke.
      [1913 Webster]

   2. (Civil Law) The claiming a thing as one's own; the
      asserting of a right or title in, or to, a thing.
      --Burrill.
      [1913 Webster]

WordNet (r) 3.0 (2006):

vindication
    n 1: the act of vindicating or defending against criticism or
         censure etc.; "friends provided a vindication of his
         position" [syn: vindication, exoneration]
    2: the justification for some act or belief; "he offered a
       persuasive defense of the theory" [syn: defense, defence,
       vindication]