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.

dome. Cupola, essentially a species of vault, constructed on a circular, elliptical, or polygonal plan, bulbous, segmental, semicircular, or pointed in vertical section. It can be built on top of a structure the plan of which is identical to that of the dome: if that wall is circular or elliptical it is a drum (often pierced with windows) as in a rotunda. However, domes usually provide a covering for a square-or rectangular-planned building or compartment, so there have to be adjustments to make the transition from the square to the circular, elliptical, or polygonal base of the cupola or dome. This can be achieved by means of pendentives (fragments (b) of a sail-vault (a, c) resembling a species of concave, distorted, almost triangular spandrels, rising up from the corner at the top of the right-angled compartment to the circular or elliptical base of the drum or cupola) or (d ) squinches (small arch or series of parallel arches of increasing radius spanning the angle of the square compartment). Both the drum and cupola will have a diameter the same dimension as the side of the square on which the whole structure stands.

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.

dome
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.

Dome Dome of the Rock an Islamic shrine in Jerusalem, for Muslims the third most holy place after Mecca and Medina. Built in the area of Solomon's temple, the shrine dates from the end of the 7th century. It surrounds the sacred rock on which, according to tradition, Abraham prepared to sacrifice his son Isaac and from which the prophet Muhammad made his miraculous midnight ascent into heaven (the Night Journey).
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.

dome In architecture, a hemispherical roof. One of the earliest monumental domes is the Pantheon, Rome. It was an important element in Islamic art and architecture, especially mosques. Eclipsed in importance in Gothic architecture, it was a significant element in Renaissance and Baroque styles.