外事司的英文：
department of foreign affairs; foreign affairs department

department是什么意思：
n. 部，司，局，科，部门；（大学的）系

A government department or a subdivision of a department.
局司处等行政单位政府部门或其下属机构

He's the departed department leader.
他是过去的部门领导。

The bulk of the work rolls from department to department.
大量的工作从一个部门转移到另一个部门。

foreign是什么意思：
adj. 外国的；不属于本身的；无关的；外交的；陌生的

In the UK, there are the Foreign Office and Foreign Secretary.
在英国，有外交部和外交大臣。

custom of foreign trade.
对外贸易惯例

The guidebook is for the accommodation of foreign tuorists.
这份指南是为了方便外国游客而准备的。

affairs是什么意思：
n. 事务；事件；风流韵事

You have to investigate into this affair.
你必须调查研究这件事。

The affair had a strange sequel.
这一事件的结局很奇怪。

A committee was constituted to investigate into that affair.
建立了一个委员会以调查那件事。