viola da gamba vs bass viol

viola da gamba and bass viol both are nouns.

Word	Noun	Adjective	Verb	Adverb
viola da gamba	Yes	No	No	No
bass viol	Yes	No	No	No

As nouns, viola da gamba and bass viol are synonyms defined as:

viola da gamba and bass viol: viol that is the bass member of the viol family with approximately the range of the cello

Other synonyms of viola da gamba include gamba.

viola da gamba (noun)	bass viol (noun)
viol that is the bass member of the viol family with approximately the range of the cello	viol that is the bass member of the viol family with approximately the range of the cello
	largest and lowest member of the violin family