chhèng-khang銃空

muzzle

muzzle (open end of a gun); small wall holes on a pillbox (for open fire towards the outside)

English Wiktionary, “銃空” (CC BY-SA 4.0) — https://en.wiktionary.org/wiki/%E9%8A%83%E7%A9%BA · confidence: Medium (Wiktionary)