“双约会或四人约会”用英语表达是 double date，它表示：

1、a date on which two couples go together
两对情侣一起去的约会

2、an occasion when two couples go out together
两对情侣一起外出的场合

3、a date where two people and their partners go together
两个人和他们的伴侣一起去约会

4、a social engagement in which two couples participate together
两对夫妇一起参加的社交活动

例如：

1、When Jim and Sam went on a double date with their girlfriends, they had a fun evening together.
吉姆和萨姆和他们的女朋友去了一次双人约会，他们在一起度过了一个愉快的夜晚。

2、Well, now that you are dating my girlfriend's brother, we can go on a double date sometime; it would really be fun, what do you say?
好吧，既然你和我女朋友的弟弟约会了，我们可以找个时间来个双人约会；那真的很有趣，你说呢？

解析：sometime 作为副词的时候，表示某一个不太确切、没法确定的某个时间，既可以指过去也可以指将来。

3、They had gone on a double date with another couple who were their friends, and had a really good time together.
他们和另一对朋友进行了一次双人约会，在一起过得非常愉快。

4、When they went on a date to the restaurant, they met an old friend who was on a date with his partner, so they joined up and had a double date.
当他们去餐馆约会时，他们遇到了一个老朋友，他正在和他的搭档约会，于是他们联合他们的老朋友并进行了一次双人约会。

解析：join up (with sb) 表示 （与某人）联合，会合。

5、Bill asked two girls at the club whether they would like to go on a double date with him and his friend.
比尔问俱乐部里的两个女孩是否愿意和他和他的朋友约会。