Source : Webster's Revised Unabridged Dictionary (1913)

Identity \I*den"ti*ty\, n.; pl. {Identities}. [F. identit['e],
   LL. identitas, fr. L. idem the same, from the root of is he,
   that; cf. Skr. idam this. Cf. {Item}.]
   1. The state or quality of being identical, or the same;
      sameness.

            Identity is a relation between our cognitions of a
            thing, not between things themselves. --Sir W.
                                                  Hamilton.

   2. The condition of being the same with something described
      or asserted, or of possessing a character claimed; as, to
      establish the identity of stolen goods.

   3. (Math.) An identical equation.

Source : WordNet®

identity
     n 1: the distinct personality of an individual regarded as a
          persisting entity; "you can lose your identity when you
          join the army" [syn: {personal identity}, {individuality}]
     2: the individual characteristics by which a thing or person is
        recognized or known; "geneticists only recently discovered
        the identity of the gene that causes it"; "it was too dark
        to determine his identity"; "she guessed the identity of
        his lover"
     3: an operator that leaves unchanged the element on which it
        operates; "the identity under numerical multiplication is
        1" [syn: {identity element}, {identity operator}]
     4: exact sameness; "they shared an identity of interests" [syn:
         {identicalness}, {indistinguishability}]