n. An early stringed instrument similar to a double bass; a double bass viol
the GNU version of the Collaborative International Dictionary of English
n. The largest instrument of the bass-viol kind, having strings tuned an octave below those of the violoncello; the contrabasso; -- called also double bass.
The Century Dictionary and Cyclopedia
n. The largest of the medieval viols; a double-bass viol.
n. In organ-building, a pedal stop of sixteenfeet tone, resembling the violoncello.
Word Usage
"And No. 6 is a marvel, its dark hues never eclipsing the dancelike rhythms of the music and the fascinating interplay among viola, cello, viola da gamba and violone."