1 Bowl-shaped vault on a circular, elliptical, or polygonal plan.
2 Underside or soffit of a dome.
3 Bowl-shaped element carried on columns set as a canopy over a tomb, etc., or a ciborium.
4 Small dome on the lantern over the eye of a large dome, or the dome plus lantern, or any diminutive domed form, visible above a roof.
5 Revolving dome of an observatory, or an armoured revolving dome over the guns of a fortress.