quartet vs IV

quartet and IV both are nouns.

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

As nouns, quartet and IV are synonyms defined as:

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

quartet (noun)	IV (noun)
a musical composition for four performers	administration of nutrients through a vein
four people considered as a unit	the cardinal number that is the sum of three and one
a set of four similar things considered as a unit
four performers or singers who perform together
the cardinal number that is the sum of three and one