duad vs pair

duad and pair both are nouns.

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

As nouns, duad and pair are synonyms defined as:

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

duad (noun)	pair (noun)
two items of the same kind	two people considered as a unit
	a set of two similar things considered as a unit
	a poker hand with 2 cards of the same value
	two items of the same kind

duad (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