quaternity vs tetrad

quaternity and tetrad both are nouns.

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

As nouns, quaternity and tetrad are synonyms defined as:

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

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

quaternity (noun)	tetrad (noun)
the cardinal number that is the sum of three and one	the cardinal number that is the sum of three and one