1. (n.) An enclosed place in which heat is produced by the combustion of fuel, as for reducing ores or melting metals, for warming a house, for baking pottery, etc.; as, an iron furnace; a hot-air furnace; a glass furnace; a boiler furnace, etc.

2. (n.) A place or time of punishment, affliction, or great trial; severe experience or discipline.

3. (n.) To throw out, or exhale, as from a furnace; also, to put into a furnace.

Seger cone Torrid Zone acid kiln atomic pile blacksmith shop blast furnace bloomery boiler bottle-gas stove breeder reactor brickkiln bricks burner butane stove calefactor caliduct cement kiln chain reactor chain-reacting pile coal furnace coal stove cook stove cooker cookery element enamel kiln equator fast pile forge foundry gas jet gas stove heater heating duct hell heterogeneous reactor homogeneous reactor inferno intermediate pile jet kiln kitchener lattice limekiln metalworks muffle kiln neutron factory nuclear furnace oven pile pilot light plutonium reactor power reactor power-breeder reactor pyrometer pyrometric cone radioactive waste range reactor reactor pile reverberatory reverberatory kiln rods salamander salamander stove slow pile smelter smithery smithy steam bath steam pipe steel mill steelworks stellarator stithy stove subtropics tewel tropics tuyere uranium reactor warmer