Source : Webster's Revised Unabridged Dictionary (1913)

Eighth \Eighth\, a. [AS. eahto?a.]
   1. Next in order after the seventh.

   2. Consisting of one of eight equal divisions of a thing.

   {Eighth note} (Mus.), the eighth part of a whole note, or
      semibreve; a quaver.

Source : WordNet®

eighth note
     n : a musical note having the time value of an eighth of a whole
         note [syn: {quaver}]