quartette vs piece of music

quartette and piece of music both are nouns.

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

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

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

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