definition of
[foursome]

[1] #1 foursome n. [quartet, quartette] four people considered as a unit; "he joined a barbershop quartet"; "the foursome teed off before 9 a.m.". wn

[2] #2 foursome n. [four, 4, IV, tetrad, quatern, quaternion, quaternary, quaternity, quartet, quadruplet, Little Joe] the cardinal number that is the sum of three and one. wn