Synonyms for Bass Viol (same or very similar meaning)
WordNet sense 1 (viol that is the bass member of the viol family with approximately the range of the cello):
viola da gamba, gambaWordNet sense 2 (largest and lowest member of the violin family):
contrabass, bass fiddle, bull fiddle, double bass, string bassFrom the ODE community, based on WordNetadd/edit