duette vs piece of music

duette and piece of music both are nouns.

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

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

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

duette (noun)	piece of music (noun)
a musical composition for two performers	a musical work that has been created
two performers or singers who perform together