cupola
cupola /ˈkyo͞opələ/ I. noun 1. a small dome, especially a small dome on a drum on top of a larger dome, adorning a roof or ceiling. 2. a gun turret; a small domed hatch above a gun turret on some tanks. 3. (also cupola furnace) — a cylindrical furnace for refining metals, with openings at the bottom for blowing in air and originally with a dome leading to a chimney above. II. derivatives cupolaed adjective – origin mid 16th cent.: Italian, from late Latin cupula ‘small cask or burying vault,’ diminutive of cupa ‘cask.’
