Source : Webster's Revised Unabridged Dictionary (1913)

Overtone \O"ver*tone`\, n. [A translation of G. oberton. See
   {Over},{Tone}.] (Mus.)
   One of the harmonics faintly heard with and above a tone as
   it dies away, produced by some aliquot portion of the
   vibrating sting or column of air which yields the fundamental
   tone; one of the natural harmonic scale of tones, as the
   octave, twelfth, fifteenth, etc.; an aliquot or ``partial''
   tone; a harmonic. See {Harmonic}, and {Tone}. --Tyndall.

Source : WordNet®

overtone
     n 1: (usually plural) an ulterior implicit meaning or quality;
          "overtones of despair"
     2: a harmonic with a frequency that is a multiple of the
        fundamental frequency [syn: {partial}, {partial tone}]