hautbois vs basset oboe

hautbois and basset oboe both are nouns.

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

As nouns, basset oboe is a hyponym of hautbois; that is, basset oboe is a word with a more specific, narrower meaning than hautbois:

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

Other hyponyms of hautbois include heckelphone, musette pipe, oboe da caccia, oboe d'amore, shawm.

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