basset oboe vs hautbois

basset oboe and hautbois both are nouns.

Word	Noun	Adjective	Verb	Adverb
basset oboe	Yes	No	No	No
hautbois	Yes	No	No	No

As nouns, hautbois is a hypernym of basset oboe; that is, hautbois is a word with a broader meaning than basset oboe:

basset oboe: an oboe pitched an octave below the ordinary oboe
hautbois: a slender double-reed instrument; a woodwind with a conical bore and a double-reed mouthpiece

Other hypernyms of basset oboe include hautboy, oboe.

basset oboe (noun)	hautbois (noun)
an oboe pitched an octave below the ordinary oboe	a slender double-reed instrument; a woodwind with a conical bore and a double-reed mouthpiece