bunghole

名词 bunghole:

1. a hole in a barrel or cask; used to fill or empty it

bung.hole

n.（名词）
The hole in a cask, keg, or barrel through which liquid is poured in or drained out.
桶孔，桶口：木桶、小桶或桶上用来倒入或倒出液体的洞