In architecture, a cupola /ˈkjuːpələ/ 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 Greek κύπελλον kupellon) 'small cup' (Latin cupa) indicating a vault resembling an upside-down cup.