A classic and reoccurring form in architecture, the dome has graced buildings throughout architectural history and across the globe. In architecture, the dome is simply a hollow semi-spherical structural element, yet in practice, the dome has taken on a defining role in the organisation of interior and exterior space in the built environment and developed a high level of specialisation by types.
One of the earliest dome forms found in several paleolithic constructions, the corbel dome is not, strictly speaking, a dome, because it is formed by horizontal masonry constructions that gradually decrease in size to create a semi-spherical shape. As the circumference of each layer decreases, the masonry circles gradually move toward the centre, supported by the previous layer until the shape is completely closed at the top.
Commonly found in eastern architecture, the onion dome is a bulbous dome that widens from a small base and then tapers toward the top, similar to the dome of the Taj Mahal or many Russian Orthodox church domes.
Perhaps the most common dome shape, the drum dome is a simple semi-spherical shape that extends up from a circular base, similar to the dome of the Pantheon.
Often found in Baroque or late Renaissance buildings, the oval dome has an oval or egg-shaped base and extends upward much like a spherical dome.
The sail dome is unique because, unlike the drum dome, its base does not form a circle. Rather, corners of the dome support the entire structure, while the remaining sides also curve up, creating a shape much like a square sail blowing in the wind.
The term saucer dome is applied to circular-based domes that, unlike a drum dome, create a low-pitched shape that looks more like an inverted saucer than a half sphere.
A scalloped dome or umbrella dome is a dome in which the weight of the dome is supported by vertical structures that go from the base to the centre, dividing the dome into segments. If the vertical lines distort the shape of the dome, so that each cross-section is polygonal rather than circular, the dome is called a polygonal dome. Thomas Jefferson's Monticello, for example, is a polygonal dome.