double bassoon vs bassoon

double bassoon and bassoon both are nouns.

Word	Noun	Adjective	Verb	Adverb
double bassoon	Yes	No	No	No
bassoon	Yes	No	No	No

As nouns, bassoon is a hypernym of double bassoon; that is, bassoon is a word with a broader meaning than double bassoon:

double bassoon: the bassoon that is the largest instrument in the oboe family
bassoon: a double-reed instrument; the tenor of the oboe family

double bassoon (noun)	bassoon (noun)
the bassoon that is the largest instrument in the oboe family	a double-reed instrument; the tenor of the oboe family