pop-hole - 빌딩 측면 구멍 (입구), 커버로 만들어짐, 적은 동물들이 건물을 들락날락할 수 있게 만든 '입구'
a hole in the side of building, usually with a cover that can be opened and closed, through which small
animals go in and out of the building:
The hens have access to the outside through pop-holes along the walls.
Pop-holes make it easier to catch piglets for handling.
Another requirement is the provision of pop holes (the way in and out of chicken houses)