three vs trio

three and trio both are nouns.

Word	Noun	Adjective	Verb	Adverb
three	Yes	Yes	No	No
trio	Yes	No	No	No

As nouns, three and trio are synonyms defined as:

three and trio: the cardinal number that is the sum of one and one and one

three (noun)	trio (noun)
one of four playing cards in a deck having three pips	a musical composition for three performers
the cardinal number that is the sum of one and one and one	three people considered as a unit
	a set of three similar things considered as a unit
	three performers or singers who perform together
	the cardinal number that is the sum of one and one and one

three (adjective)	trio (adjective)
being one more than two