dome / dōm/ • n. 1. a rounded vault forming the roof of a building or structure, typically with a circular base: the dome of St. Paul's Cathedral. ∎ the revolving openable hemispherical roof of an observatory. ∎ [in names] a sports stadium with a domed roof.2. a thing shaped like such a roof, in particular: ∎ the rounded summit of a hill or mountain: the great dome of Mont Blanc. ∎ a natural vault or canopy, such as that of the sky or trees: the dome of the sky. ∎ Geol. a rounded uplifted landform or underground structure. ∎ inf. the top of the head: a content face topped by a shaved dome.3. poetic/lit. a stately building.• v. [tr.] [usu. as adj.] (domed) cover with or shape as a dome: a domed stadium. ∎ [intr.] [often as n.] (doming) (of stratified rock or a surface) become rounded in formation; swell.DERIVATIVES: dome·like / -ˌlīk/ adj.
Types of drum include:calotte: low cupola or saucer-dome of segmental vertical section;, like a skull-cap;cloister-vault: as domical vault below;domical vault: cloister-vault, not a true dome, but formed of four or more (depending on the shape of the base) cells or webs forming groins where they touch vertically and rising to a point;melon: as parachute below;Pantheon: low dome on the exterior, often stepped, resembling that of the Pantheon in Rome, and coffered on the interior, widely copied by Neo-Classical architects;parachute; melon, pumpkin, or umbrella dome standing on a scalloped circular base and formed of individual webs, segmental on plan, joining in groins or ribs. Each web has a concave interior and convex exterior so it resembles a parachute, rather than an umbrella;pumpkin: as parachute above;sail-dome (a): dome resembling a billowing sail over a square compartment with its diameter the same dimension as the diagonal instead of the side of the square below, enabling the structure to rise as though on pendentives but continuing without interruption. Pendentives are really parts of a sail-dome and themselves are a species of sail-vault;umbrella: as parachute above.
1. Anticlinal structure which plunges in all directions.
2. (volcanic dome, tholoid) A mound of viscous lava, usually rhyolite in composition, which has grown and built up over a vent. The mound of solid lava is covered by coarse, angular blocks which form by chilling and brecciation of the growing dome's surface. The blocks accumulate around the growing dome to produce a scree slope of crumble breccia. Domes can grow by repeated injection of magma into the dome body (endogenous dome) or by repeated eruption of small volumes of magma from the surface of the dome (exogenous dome).
3. (salt dome) A circular or elongate plug, 1–2 km in diameter but extending downwards for many kilometres, formed by the upward movement of buoyant and less dense evaporitic material (commonly halite) into denser overlying rocks. The diapiric movement (see DIAPIR) may be initiated by tectonic thickening.
4. A special form of crystal development characterized by two roof-like faces symmetrical about a plane of symmetry. The faces are repeated once only about an axis of symmetry.
5. See PERICLINE.
6. See ICE DOME.
Millennium Dome a large building resembling a giant dome erected at Greenwich in London to house a national exhibition celebrating British achievements at the millennium. The Dome was formally opened to visitors by invitation on New Year's Eve 1999, and subsequently to the general public; it closed a year later.