noun
headroom
Refers to the vertical space above a person's head, especially in vehicles, doorways, or architectural contexts.
この車はヘッドルームが広いので、背の高い人でも快適です。
This car has ample headroom, so even tall people can ride comfortably.
階段のヘッドルームが低
The headroom on the stairs was so low I almost hit my head.