Difference in usage between クラス and 学級


What is the difference in usage/meaning between クラス and 学級? Why did I never
learn the latter in language classes?




クラス at school can refer to:

  1. a group of students who learn together (このクラスには生徒が35人います。)
  2. a lesson, a lecture (5分後に数学のクラスが始まります)

In kanji, the former is 学級, and the latter is 授業/講義.

学級 and クラス (in the first meaning) are basically interchangeable, but 学級 is
typically used in elementary and middle schools. For some reasons, people
start to prefer クラス maybe after entering high school. (Does this explain why
you didn't learn 学級?)

> [学級 - Wikipedia](http://ja.wikipedia.org/wiki/%E5%AD%A6%E7%B4%9A)  
>  一般には、 **幼稚園・小学校・中学校などで** 、幼児・児童・生徒などが学校生活の大半の時間を過ごす場

And there are many set phrases where only one of the two can be used. For
example, クラス替え is usually not called 学級替え, and 学級閉鎖 (due to flu outbreak,
etc.) is far more common than クラス閉鎖.

