Source : Webster's Revised Unabridged Dictionary (1913)

Harmonica \Har*mon"i*ca\, n. [Fem. fr. L. harmonicus harmonic.
   See {Harmonic}, n. ]
   1. A musical instrument, consisting of a series of
      hemispherical glasses which, by touching the edges with
      the dampened finger, give forth the tones.

Source : WordNet®

harmonica
     n : a small rectangular free-reed instrument having a row of
         free reeds set back in air holes and played by blowing
         into the desired hole [syn: {mouth organ}, {harp}, {mouth
         harp}]