waiting room; duty room; staff room
A room where people wait, especially for work or duty, such as a standby room for staff or a waiting area in a facility.
The doctor waited in the duty room to be called.
スタッフは待機室で次の指示を待っている。
The staff are waiting in the staff room for the next instructions.
Compound of 待機 (standby, waiting) and 室 (room).