Dome

in architecture, a hollow hemisphere resting on pillars, or a supporting wall. The dome grew out of the arch, and is regarded as an invention of the Roman builders. Some of the noted domes of the world are those of the Pantheon and St. Peter's at Rome; St. Paul's, London; St. Sophia at Constantinople; the Hotel des Invalides of Paris, under which Napoleon lies; Santa Maria at Florence, and that of our own National Capitol at Washington. Cupola is a synonymous term. The open space or hall beneath a dome is called a rotunda. See Capitol; St. Peter'S; St. Paul'S