double reed vs bassoon

double reed and bassoon both are nouns.

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

As nouns, bassoon is a hyponym of double reed; that is, bassoon is a word with a more specific, narrower meaning than double reed:

double reed: a woodwind that has a pair of joined reeds that vibrate together
bassoon: a double-reed instrument; the tenor of the oboe family

Other hyponyms of double reed include cor anglais, English horn, cromorne, crumhorn, krummhorn, hautbois, hautboy, oboe.

double reed (noun)	bassoon (noun)
a pair of joined reeds that vibrate together to produce the sound in some woodwinds	a double-reed instrument; the tenor of the oboe family
a woodwind that has a pair of joined reeds that vibrate together