Source : Webster's Revised Unabridged Dictionary (1913)

Bass \Bass\, a.
   Deep or grave in tone.

   {Bass clef} (Mus.), the character placed at the beginning of
      the staff containing the bass part of a musical
      composition. [See Illust. under {Clef}.]

   {Bass voice}, a deep-sounding voice; a voice fitted for
      singing bass.

Source : WordNet®

bass voice
     n : the lowest adult male singing voice [syn: {bass}, {basso}]