noun
burner; nozzle; origin of a fire
Refers to the opening or outlet of a burner or nozzle, or the point where a fire starts. Common in technical, industrial, and fire investigation contexts.
ガスコンロの火口を掃除した。
I cleaned the burner of the gas stove.
消防は火口の特定に時間がかかった。
The fire department took time to identify the origin of the fire.