Source : Webster's Revised Unabridged Dictionary (1913)

Violone \Vi`o*lo"ne\, n. [It. violone, augment. of viola a viol.
   See {Viol}.] (Mus.)
   The largest instrument of the bass-viol kind, having strings
   tuned an octave below those of the violoncello; the
   contrabasso; -- called also {double bass}. [Written also
   {violono}.]