twosome vs duet

twosome and duet both are nouns.

Word	Noun	Adjective	Verb	Adverb
twosome	Yes	No	No	No
duet	Yes	No	No	No

As nouns, twosome and duet are synonyms defined as:

Other synonyms of twosome include couple, duo.

As nouns, twosome and duet are synonyms defined as:

Other synonyms of twosome include brace, couple, couplet, distich, duad, duo, dyad, pair, span, twain, yoke.

twosome (noun)	duet (noun)
a pair who associate with one another	(ballet) a dance for two people (usually a ballerina and a danseur noble)
two items of the same kind	a musical composition for two performers
	a pair who associate with one another
	two performers or singers who perform together
	two items of the same kind