string quartette vs quartet

string quartette and quartet both are nouns.

Word	Noun	Adjective	Verb	Adverb
string quartette	Yes	No	No	No
quartet	Yes	No	No	No

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

string quartette: an instrumental quartet with 2 violins and a viola and a cello
quartet: four performers or singers who perform together

Other hypernyms of string quartette include quartette.

string quartette (noun)	quartet (noun)
an instrumental quartet with 2 violins and a viola and a cello	a musical composition for four performers
	four people considered as a unit
	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