Cupola

Cupola (Ital., from the root of cup), a spherical vault, or concave ceiling, on the top of a building; the internal part of a Dome (q.v.). The term is also sometimes used for a dome which is ogival (not hemispherical or semi-elliptical) in outline, or for a small dome. Cupolas are often wholly or partially of glass. There are cupola-furnaces; see IRON.