Noun
A stringed instrument of the viol family, used for playing bass. See 3d Bass, n., and Violoncello.
Source: Webster's dictionarybass-viol
Currently, the term "viola da gamba" without qualification generally refers to the bass viol. Source: Internet
Subject matter depicts amateur social music making, featuring lute, bass viol, and singers, with part books spread around the table. Source: Internet