charcoal kiln; charcoal pile
A kiln or covered pile used for producing charcoal from wood. Both 炭窯 and 炭竈 refer to the same thing, but 炭窯 is the more common spelling.
An old charcoal kiln remains deep in the mountains.
炭窯で木を蒸し焼きにして炭を作る。
They make charcoal by smoldering wood in a charcoal kiln.
Standard kanji spelling using 窯 (kiln).
Variant using 竈 (kamado/hearth), less common in modern usage.
Compound of 炭 (sumi, 'charcoal') and 窯 (kama, 'kiln'). The variant 炭竈 uses 竈 (kamado, 'hearth/kiln'), an older character for a similar structure.