Source : Webster's Revised Unabridged Dictionary (1913)

Dissonance \Dis"so*nance\, n. [L. dissonantia: cf. F.
   dissonance.]
   1. A mingling of discordant sounds; an inharmonious
      combination of sounds; discord.

            Filled the air with barbarous dissonance. --Milton.

   2. Want of agreement; incongruity. --Milton.

Source : WordNet®

dissonance
     n 1: a conflict of people's opinions or actions or characters
          [syn: {disagreement}, {dissension}] [ant: {agreement}]
     2: the auditory experience of sound that lacks musical quality;
        sound that is a disagreeable auditory experience; "modern
        music is just noise to me" [syn: {noise}, {racket}]
     3: disagreeable sounds [ant: {harmony}]