Cupola

In architecture, a cupola (/ˈk(j)uːpələ/) is a relatively small, most often dome-like, tall structure on top of a building. Often used to provide a lookout or to admit light and air, it usually crowns a larger roof or dome.

The word derives, via Italian, from lower Latin cupula (classical Latin cupella), from Ancient Greek κύπελλον (kúpellon) 'small cup' (Latin cupa), indicating a vault resembling an upside-down cup.