銃口

1. Origins, structure, and basic meaning

• Structure: The weapon-part noun 銃口 (じゅうこう) is the muzzle, the open end of a gun barrel.
• Basic usage: It is commonly the object of a direction phrase, as in 銃口を下に向ける or 地面へ向ける.

2. Common pitfalls and similar expressions

• The muzzle and its direction
  • It identifies the barrel opening and its direction, not the whole firearm or its trigger.