Private Room
One's Own Room
noun
こしつ
個室 （こしつ） Private Room, One's Own Room
寝室 （しんしつ、not on WK） Bedroom
His Private Room 個室 also happens to be a small 小 こ room 室 しつ
The child 子 こ shit しつ in his Private Room.
There's a child 子 こ shih-tzu しつ in his Private Room.