1. 四人组;四个事物的组合
A foursome is a group of four people or things.
1. four people considered as a unit
e.g. he joined a barbershop quartet
the foursome teed off before 9 a.m.
Synonym: quartetquartette
2. the cardinal number that is the sum of three and one
Synonym: four4IVtetradquaternquaternionquaternaryquaternityquartetquadrupletLittle Joe