quatern vs quaternity

quatern and quaternity both are nouns.

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

As nouns, quatern and quaternity are synonyms defined as:

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

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

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