duet vs pair

duet and pair both are nouns.

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

As nouns, pair is a hypernym of duet; that is, pair is a word with a broader meaning than duet:

As nouns, duet and pair are synonyms defined as:

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

duet (noun)	pair (noun)
(ballet) a dance for two people (usually a ballerina and a danseur noble)	two people considered as a unit
a musical composition for two performers	a set of two similar things considered as a unit
a pair who associate with one another	a poker hand with 2 cards of the same value
two performers or singers who perform together	two items of the same kind
two items of the same kind

duet (verb)	pair (verb)
	engage in sexual intercourse
	bring two objects, ideas, or people together
	arrange in pairs
	occur in pairs
	form a pair or pairs