quatern vs quaternion

quatern and quaternion both are nouns.

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

As nouns, quatern and quaternion are synonyms defined as:

quatern and quaternion: 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, quaternity, tetrad.

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