double reed vs double-reed instrument

double reed and double-reed instrument both are nouns.

Word	Noun	Adjective	Verb	Adverb
double reed	Yes	No	No	No
double-reed instrument	Yes	No	No	No

As nouns, double reed and double-reed instrument are synonyms defined as:

double reed and double-reed instrument: a woodwind that has a pair of joined reeds that vibrate together

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