noun
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
I made a small garden on the rooftop.