bull fiddle vs double bass

bull fiddle and double bass both are nouns.

Word	Noun	Adjective	Verb	Adverb
bull fiddle	Yes	No	No	No
double bass	Yes	No	No	No

As nouns, bull fiddle and double bass are synonyms defined as:

bull fiddle and double bass: largest and lowest member of the violin family

Other synonyms of bull fiddle include bass fiddle, bass viol, contrabass, string bass.

bull fiddle (noun)	double bass (noun)
largest and lowest member of the violin family	largest and lowest member of the violin family