double reed vs hautboy

double reed and hautboy both are nouns.

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

As nouns, hautboy is a hyponym of double reed; that is, hautboy 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
hautboy: a slender double-reed instrument; a woodwind with a conical bore and a double-reed mouthpiece

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

double reed (noun)	hautboy (noun)
a pair of joined reeds that vibrate together to produce the sound in some woodwinds	a slender double-reed instrument; a woodwind with a conical bore and a double-reed mouthpiece
a woodwind that has a pair of joined reeds that vibrate together