FOURSOME
quartet, quartette, foursome
(noun) four people considered as a unit; “he joined a barbershop quartet”; “the foursome teed off before 9 a.m.”
four, IV, tetrad, quatern, quaternion, quaternary, quaternity, quartet, quadruplet, foursome, Little Joe
(noun) the cardinal number that is the sum of three and one
Source: WordNet® 3.1
Etymology
Noun
foursome (plural foursomes)
A group of four, a quartet or a game (such as golf) played by four players, especially by two teams of two.
A sex act between four people.
Synonyms
• (group of four): quaternion, tetrad; see also quartet
• (sex act): fourgie
Source: Wiktionary
Four"some, a. [Four + 2d -some.]
Definition: Consisting of four; requiring four participants. [Scot. or
Golf]
Four"some, n. (Golf)
Definition: A game between four players, with two on each side and each
side playing but one ball, the partners striking alternately. It is
called a mixed foursome when each side consists of a man and a woman.
Source: Webster’s Unabridged Dictionary 1913 Edition