Cupola

Pronunciation: k?"p?-l?
n. pl. Cupolas (-lz).

1. (Arch.) A roof having a rounded form, hemispherical or nearly so; also, a ceiling having the same form. When on a large scale it is usually called dome.
2. A small structure standing on the top of a dome; a lantern.
3. A furnace for melting iron or other metals in large quantity, -- used chiefly in foundries and steel works.
4. A revolving shot-proof turret for heavy ordnance.
5. (Anat.) The top of the spire of the cochlea of the ear.