Translation guide
The top covering of a building, vehicle, or structure. In Japanese, the most common word is 屋根 (yane) for buildings, but other terms apply to specific contexts like cars, mouths, or metaphorical roofs.
The top covering of a house, building, or structure.
The standard word for the roof of a building. Used in everyday conversation.
There is a cat on the roof.
雨漏りがするので屋根を修理しないといけない。
The roof is leaking, so I have to repair it.
Rooftop, specifically a flat roof area used as a space, like on a building where people can go. Not for sloped roofs.
屋上から花火を見た。
We watched fireworks from the rooftop.
Loanword from English, used in some compound terms or stylish names, but not common for ordinary roofs.
ルーフバルコニー
roof balcony
The top part of a car, bus, or train.
Also used for vehicle roofs, though context makes it clear.
車の屋根に雪が積もっている。
Snow is piled up on the car roof.
Common in automotive contexts, e.g., sunroof, roof rack.
サンルーフ付きの車
a car with a sunroof
The upper inside surface of the mouth.
Anatomical term for the palate. Used in medical or formal contexts.
口蓋に口内炎ができた。
I got a canker sore on the roof of my mouth.
Colloquial expression meaning 'ceiling of the mouth'. More common in everyday speech than 口蓋.
熱いピザで口の中の天井をやけどした。
I burned the roof of my mouth on hot pizza.
A figurative upper limit or covering, like a price ceiling or the top of the world.
Means ceiling, but used metaphorically for upper limits (e.g., price ceiling, glass ceiling).
ガラスの天井を打ち破る。
Break through the glass ceiling.
価格の天井が設定されている。
A price ceiling has been set.
Upper limit, cap. More direct for numerical or regulatory limits.
The overhead rock surface inside a cave or tunnel.
Used for the ceiling/roof of caves, tunnels, and mines.
洞窟の天井からつららが下がっている。
Icicles are hanging from the cave roof.
屋根 (yane) is the exterior roof, the top covering of a building. 天井 (tenjō) is the interior ceiling, the surface you see from inside a room. Do not confuse them.
屋根が雨漏りしている。
The roof is leaking.
天井に照明がついている。
There is a light on the ceiling.
The loanword ルーフ is mainly used in automotive or stylistic compound words. Using it for a house roof sounds unnatural. Stick to 屋根.
屋根が雨漏りしている。
The roof is leaking.
屋上に上がった。
We went up to the roof.
口の中の天井をやけどした。
I burned the roof of my mouth.
予算の上限は100万円です。
The budget ceiling is 1 million yen.