quadruplet vs quartet

quadruplet and quartet both are nouns.

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

As nouns, quadruplet and quartet are synonyms defined as:

quadruplet and quartet: a set of four similar things considered as a unit

Other synonyms of quadruplet include quadruple, quartette.

As nouns, quadruplet and quartet are synonyms defined as:

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

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

quadruplet (noun)	quartet (noun)
a set of four similar things considered as a unit	a musical composition for four performers
one of four children born at the same time from the same pregnancy	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