noun
The overhead interior surface of a room. Also used figuratively for an upper limit.
部屋の天井が高い。
The ceiling of the room is high.
天井に照明を取り付けた。
I installed a light on the ceiling.
noun
ceiling price; upper limit
Economic term for a maximum allowable price or value. Often used in financial contexts.
政府はガソリン価格に天井を設けた。
The government set a ceiling on gasoline prices.