bass viol

from WordNet (r) 3.0 (2006)

bass viol
    n 1: viol that is the bass member of the viol family with
         approximately the range of the cello [syn: {viola da
         gamba}, {gamba}, {bass viol}]
    2: largest and lowest member of the violin family [syn: {bass
       fiddle}, {bass viol}, {bull fiddle}, {double bass},
       {contrabass}, {string bass}]

from The Collaborative International Dictionary of English v.0.48

Bass viol \Bass" vi`ol\ (Mus.)
   A stringed instrument of the viol family, used for playing
   bass. See 3d {Bass}, n., and {Violoncello}.
   [1913 Webster]