A furnace's a device used for heating. The name derives from Latin fornax, oven. The earliest furnace was excavated at Balakot, a site of the Indus Valley Civilization, dating back to its mature phase (c. 2500-1900 BC). The furnace was most likely used for the manufacturing of ceramic objects. In American English and Canadian English, the term furnace on its own's generally used to describe household heating systems based on a central furnace (known either as a boiler or a heater in British Eng… (More on Furnace)