quartet vs digit

quartet and digit both are nouns.

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

As nouns, digit is a hypernym of quartet; that is, digit is a word with a broader meaning than quartet:

Other hypernyms of quartet include figure.

quartet (noun)	digit (noun)
a musical composition for four performers	a finger or toe in human beings or corresponding body part in other vertebrates
four people considered as a unit	one of the elements that collectively form a system of numeration
a set of four similar things considered as a unit	the length of breadth of a finger used as a linear measure
four performers or singers who perform together
the cardinal number that is the sum of three and one