quintuplet vs fivesome

quintuplet and fivesome both are nouns.

Word	Noun	Adjective	Verb	Adverb
quintuplet	Yes	No	No	No
fivesome	Yes	No	No	No

As nouns, quintuplet and fivesome are synonyms defined as:

quintuplet and fivesome: the cardinal number that is the sum of four and one

Other synonyms of quintuplet include 5, cinque, fin, five, Little Phoebe, pentad, Phoebe, quint, quintet, V.

quintuplet (noun)	fivesome (noun)
a set of five similar things considered as a unit	five people considered as a unit
one of five children born at the same time from the same pregnancy	the cardinal number that is the sum of four and one
the cardinal number that is the sum of four and one