Traditional oasts (also called oast houses) are conical, with two or three levels, and with a kiln at the bottom to provide hot air. A cowl was attached at the top of the conical roof, to keep out weather and promote air flow.
Etymology: Middle English ost, kiln. Oasts have been around for at least 400 years, but have now been replaced by industrial dryers. Some surviving oast houses have been converted into residences, theaters, or shops.