furnace

Etymology

From Middle English forneys, from Old French fornais (French fournaise), from Latin fornāx.

noun

1. An industrial heating device, such as for smelting metal or firing ceramics.
   Plans for the next phase include furnaces capable of inert atmospheres and partial vacuums.
2. (US, Canada) A device that provides heat for a building.
   HVAC services include furnace maintenance.
3. (colloquial, figurative) Any area that is excessively hot.
   The busy kitchen became a sweltering furnace.
4. (figurative) A place or time of punishment, affliction, or great trial; severe experience or discipline.
   forged in the furnace of fierce competition
   For that heroic band—those children of the furnace who, in regions like Texas and Tennessee, maintained their fidelity through terrible trials—we of the North felt for them, and profoundly we honor them. 1866, Herman Melville, Battle-Pieces and Aspects of the War, Supplement

verb

1. To heat in a furnace.
2. To exhale like a furnace.