rooftop
Refers to the top surface of a building, often accessible. Common in compounds like 屋上庭園 (rooftop garden).
See also: 屋上庭園 (おくじょうていえん)
このビルの屋上からは街が一望できる。
From the rooftop of this building, you can see the whole city.
屋上に小さな庭を作った。
I made a small garden on the rooftop.
We went up to the rooftop to watch the fireworks.
I looked at the city view from the rooftop.
The children are playing on the rooftop.