Source : Webster's Revised Unabridged Dictionary (1913)

Vox \Vox\, n. [L. See {Voice}.]
   A voice.

   {Vox humana}[L., human voice] (Mus.), a reed stop in an
      organ, made to imitate the human voice.

Source : WordNet®

vox humana
     n : an organ reed stop producing tones imitative of the human
         voice