IV vs quadruplet

IV and quadruplet both are nouns.

Word	Noun	Adjective	Verb	Adverb
IV	Yes	No	No	No
quadruplet	Yes	No	No	No

As nouns, IV and quadruplet are synonyms defined as:

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

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