quaternion vs foursome

quaternion and foursome both are nouns.

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

As nouns, quaternion and foursome are synonyms defined as:

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

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

quaternion (noun)	foursome (noun)
the cardinal number that is the sum of three and one	four people considered as a unit
	the cardinal number that is the sum of three and one