noun
rooftop amusement park
A small amusement park or play area built on the roof of a building, often a department store.
デパートの屋上遊園地で子供を遊ばせた。
I let the kids play at the department store's rooftop amusement park.
Compound of 屋上 (rooftop) and 遊園地 (amusement park).