quaternity vs quartet

quaternity and quartet both are nouns.

Word	Noun	Adjective	Verb	Adverb
quaternity	Yes	No	No	No
quartet	Yes	No	No	No

As nouns, quaternity and quartet are synonyms defined as:

quaternity and quartet: the cardinal number that is the sum of three and one

Other synonyms of quaternity include 4, four, foursome, IV, Little Joe, quadruplet, quatern, quaternary, quaternion, tetrad.

quaternity (noun)	quartet (noun)
the cardinal number that is the sum of three and one	a musical composition for four performers
	four people considered as a unit
	a set of four similar things considered as a unit
	four performers or singers who perform together
	the cardinal number that is the sum of three and one