In architecture, a cupola (/ˈkjuːpələ, ˈkuː-/)[1] is a relatively small, most often dome-like, tall structure on top of a building.[2] Often used to provide a lookout or to admit light and air, it usually crowns a larger roof or dome.[3][4]
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.[a]
The cupola evolved during the Renaissance from the older oculus. Being weatherproof, the cupola was better suited to the wetter climates of northern Europe.[citation needed] The chhatri, seen in Indian architecture, fits the definition of a cupola when it is used atop a larger structure.[citation needed]
Cupolas often serve as a belfry, belvedere, or roof lantern above a main roof. In other cases they may crown a spire, tower, or turret.[4] Barns often have cupolas for ventilation.[5][6]
Cupolas can also appear as small buildings in their own right.
The square, dome-like segment of a North American railroad train caboose that contains the second-level or "angel" seats is also called a cupola.[7][8]