foursome

名词 foursome:

1. four people considered as a unit
   同义词：quartet, quartette
2. the cardinal number that is the sum of three and one
   同义词：four, 4, IV, tetrad, quatern, quaternion, quaternary, quaternity, quartet, quadruplet, Little Joe

1. Let's make (up) a foursome and go out to a restaurant.
   咱们四个人(两对男女)一起下饭馆吧。

four.some

n.（名词）
A group of four persons or things, especially two couples.
四人一组：四人或物一组，尤指两对
Sports Games
【体育运动】 【游戏】
A game, especially a golf match, played by four persons, two on each side.
四人对抗赛：四人玩的游戏，尤指高尔夫球赛中的双打，每边两人
The players in such a game.
对抗赛的四人：参加此种游戏的人

来源：
Middle English four-som
中古英语 four-som
from Old English fôowra sum [one of four]
源自 古英语 fôowra sum [四人中的一个]
fôowra [genitive pl. of] fôower [four] * see four
fôowra [] fôower的所有格复数 [四个] *参见 four
sum [one] * see -some 2
sum [一个] *参见 -some2