English:
confinement room
Chinese:
禁闭室
Japanese:
反省室 (はんせいしつ)

Example

"Yeesh, if Jean was listening to this... Klee might find herself grounded for an awful lot longer."

「はあ、ジンがこの話を聞いたら…きっと、クレーの反省室で過ごす時間が長くなるだろうな…」