deuce vs pair

deuce and pair both are nouns.

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

As nouns, pair is a hyponym of deuce; that is, pair is a word with a more specific, narrower meaning than deuce:

deuce: the cardinal number that is the sum of one and one or a numeral representing this number
pair: two items of the same kind

Other hyponyms of deuce include craps, snake eyes, brace, couple, couplet, distich, duad, duet, duo, dyad, span, twain, twosome, yoke.

deuce (noun)	pair (noun)
one of the four playing cards in a deck that have two spots	two people considered as a unit
a word used in exclamations of confusion	a set of two similar things considered as a unit
the cardinal number that is the sum of one and one or a numeral representing this number	a poker hand with 2 cards of the same value
a tie in tennis or table tennis that requires winning two successive points to win the game	two items of the same kind

deuce (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