quaternion vs tetrad

quaternion and tetrad both are nouns.

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

As nouns, quaternion and tetrad are synonyms defined as:

quaternion and tetrad: 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, quaternity.

quaternion (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