sextette vs piece of music

sextette and piece of music both are nouns.

Word	Noun	Adjective	Verb	Adverb
sextette	Yes	No	No	No
piece of music	Yes	No	No	No

As nouns, piece of music is a hypernym of sextette; that is, piece of music is a word with a broader meaning than sextette:

Other hypernyms of sextette include composition, musical composition, opus, piece.

sextette (noun)	piece of music (noun)
a musical composition written for six performers	a musical work that has been created
six people considered as a unit
a set of six similar things considered as a unit
six performers or singers who perform together