Source : Webster's Revised Unabridged Dictionary (1913)

Harmony \Har"mo*ny\, n.; pl. {Harmonies}. [ F. harmonic, L.
   harmonia, Gr. ? joint, proportion, concord, fr. ? a fitting
   or joining. See {Article}. ]
   1. The just adaptation of parts to each other, in any system
      or combination of things, or in things, or things intended
      to form a connected whole; such an agreement between the
      different parts of a design or composition as to produce
      unity of effect; as, the harmony of the universe.

   2. Concord or agreement in facts, opinions, manners,
      interests, etc.; good correspondence; peace and
      friendship; as, good citizens live in harmony.

   3. A literary work which brings together or arranges
      systematically parallel passages of historians respecting
      the same events, and shows their agreement or consistency;
      as, a harmony of the Gospels.

   4. (Mus.)
      (a) A succession of chords according to the rules of
          progression and modulation.
      (b) The science which treats of their construction and
          progression.

                Ten thousand harps, that tuned Angelic
                harmonies.                        --Milton.

   5. (Anat.) See {Harmonic suture}, under {Harmonic}.

   {Close harmony}, {Dispersed harmony}, etc. See under {Close},
      {Dispersed}, etc.

   {Harmony of the spheres}. See {Music of the spheres}, under
      {Music}.

   Syn: {Harmony}, {Melody}.

   Usage: Harmony results from the concord of two or more
          strains or sounds which differ in pitch and quality.
          Melody denotes the pleasing alternation and variety of
          musical and measured sounds, as they succeed each
          other in a single verse or strain.

Source : WordNet®

harmony
     n 1: compatibility in opinion and action [syn: {harmoniousness}]
     2: the structure of music with respect to the composition and
        progression of chords [syn: {musical harmony}]
     3: a harmonious state of things in general and of their
        properties (as of colors and sounds); congruity of parts
        with one another and with the whole [syn: {concord}, {concordance}]
     4: agreement of opinions [syn: {concord}, {concordance}]
     5: an agreeable sound property [ant: {dissonance}]