Little Joe vs quadruplet

Little Joe and quadruplet both are nouns.

Word	Noun	Adjective	Verb	Adverb
Little Joe	Yes	No	No	No
quadruplet	Yes	No	No	No

As nouns, Little Joe and quadruplet are synonyms defined as:

Little Joe and quadruplet: the cardinal number that is the sum of three and one

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

Little Joe (noun)	quadruplet (noun)
the cardinal number that is the sum of three and one	a set of four similar things considered as a unit
	one of four children born at the same time from the same pregnancy
	the cardinal number that is the sum of three and one