furnace
n. countablen. a large, enclosed container that produces a lot of heat. You use it to warm a house or to melt materials like metal and glass.
n. an enclosed structure in which material is heated to very high temperatures, typically for smelting metal or generating steam. In domestic contexts, refers to a central heating unit that circulates warm air through a building.
The repairman came to fix the furnace before winter started.
Workers at the steel mill must wear protective gear when they stand near the open furnace.
The industrial furnace reached temperatures high enough to liquefy iron ore, allowing the molten metal to be poured into waiting molds for casting.
From Middle English forneys, from Old French fornais (French fournaise), from Latin fornāx.
Often used metaphorically to describe an extremely hot room or environment.