foursome

(noun) four people considered as a unit. Synonyms: quartet, quartette. Examples: "He joined a barbershop quartet." "The foursome teed off before 9 a.m.."

(noun) the cardinal number that is the sum of three and one. Synonyms: four, 4, IV, tetrad, quatern, quaternion, quaternary, quaternity, quartet, quadruplet, Little Joe.