quaternion vs quaternity

quaternion and quaternity both are nouns.

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

As nouns, quaternion and quaternity are synonyms defined as:

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

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

quaternion (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