In architecture, a hemispherical [like half a ball] vault or ceiling over a circular opening. Theoretically, it is an arch rotated on its vertical axis. It rises above the central part of a building. Usually it is elevated further by being placed on a circular or many-sided base.Here are example domes: Coffered Dome of the Pantheon, Rome, c. 118-128, interior view. see thumbnail to rightAnother view of the interior. See coffer, oculus, and pantheon.Filippo Brunelleschi (architect, Italian, 1377-1446), Dome of the Cathedral of Florence ? "Il Duomo." Its construction began in 1420. Brunelleschi was the first great Italian Renaissance architect. Octagonal and ribbed, it's one of the finest domical constructions in architectural history. Another view of this dome. See lantern.