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.
The burner opening of the gas stove is dirty, so it's hard to light.
The fire department investigated the scene to determine the point where the fire started.
バーナー is the common everyday loanword for a burner device as a whole, while 火口 is the technical term for the burner's opening or nozzle specifically.
ノズル is the general loanword for any nozzle, while 火口 refers specifically to the nozzle or opening of a burner.
Written identically as 火口, かこう means a volcanic crater, while ひぐち (this entry) means a burner nozzle or the point where a fire started, so context and reading must distinguish them.
mouth · opening; hole; mouth (of a container) · entrance; exit; gate · speech; talk; gossip · taste; palate · mouth to feed · job opening; vacancy · invitation; summons · kind; sort; type · beginning; start · counter for mouthfuls, shares, stove burners · counter for swords, blades
Compound of 火 (hi, 'fire') and 口 (kuchi, 'mouth, opening'), literally 'fire mouth'. The reading ひぐち is a standard rendaku form.