noun
fuel door; stoking door; furnace door
Refers to the opening or door through which fuel is added to a furnace, stove, boiler, or similar heating device.
ストーブの焚き口から薪を入れた。
I put firewood in through the stove's fuel door.
古いボイラーの焚き口が錆びついている。
The fuel door of the old boiler is rusted.
Compound of 焚き (taki, 'burning', continuative form of 焚く) + 口 (kuchi, 'mouth, opening').