Furnace (noun)

1. An enclosed structure in which heat is produced for industrial processes or for heating buildings.
2. A very hot place, especially one thought of as hellish.
3. An appliance in a central heating system that uses a fuel, such as oil or gas, to heat the air or water that circulates through the building.
4. A device used in the production of iron or steel, in which the raw materials are heated to a high temperature.
5. A kiln or oven used in ceramics or glass-making, in which the material is fired to a high temperature.

Origin:

Middle english: from old french fournaise, from latin fornax "oven, furnace".

Examples:

1. The factory had a large furnace used to heat the metal for their products.
2. The furnace was so hot that it was like standing in the depths of hell.
3. The furnace was not working properly and the house was getting colder by the minute.
4. The steel was produced in a furnace that was fired with coal.
5. The ceramics were baked in a furnace that reached a temperature of over 2000 degrees.