(Latin: domus, house)
Architectural term, often used synonymously with cupola.
Strictly speaking it is the external part of the raised covering of which the cupola is the inner; in general it is applied to the entire covering.
It is sometimes used, as in the Italian duomo, to designate a cathedral.
A dome may be of any material and of varied construction.
It is called circular, elliptical, or polygonal according to the figure of the base.
The dome in its primitive form is of great antiquity, but was developed by the Romans and carried to Constantinople, where it became the dominant factor in church architecture.
The Roman dome, of which the Pantheon is the finest example, is a hemisphere supported by a circular wall.
Byzantine domes were placed over square apartments and had no outer covering.
Medieval builders rarely used it except in Spain and Italy.
In English Gothic it became the lantern.
The Saracens use flattened cupolas; the Arabs, a pointed dome.
New Catholic Dictionary