cupola (ˈkjuːpələ)
n
1. (Architecture) a roof or ceiling in the form of a dome
2. (Architecture) a small structure, usually domed, on the top of a roof or dome
3. (Firearms, Gunnery, Ordnance & Artillery) a protective dome for a gun on a warship
4. (Metallurgy) a vertical air-blown coke-fired cylindrical furnace in which iron is remelted for casting