Dome

Rules that use the word

The corbelled dome: rings stepping inward. Build a round chamber of horizontal courses, each ring projecting a little beyond the one below, dress the inner face to a smooth curve, close the top with a capstone, and heap earth over the whole.

Coffers that diminish towards the lantern. Divide the inside of a dome into coffers that shrink in step with the meridians as they rise, so that their perspective deepens the dome and draws the eye to the light of the lantern.

Light from a hidden source. Light the climax of a Baroque interior (the altar or the dome) from windows the visitor cannot see, so that it seems to glow of itself.

The pendentive: a sphere cut by a square. To set a round dome on a square bay, imagine a sphere passing through the four corners of the square; cut it by the four vertical planes of the sides and by the horizontal plane of their crowns. The four spherical triangles left in the corners are the pendentives; the circle at their top carries the dome.

The squinch: from square to octagon. Throw an arch diagonally across each upper corner of the square, backed by a small conch or cone; the four squinches and the four walls between them make an octagon, on which a round dome can sit.

The sail vault: one sphere, uncut. If the sphere that forms the pendentives is simply continued above the ring, the bay is covered by a single shallow dome, the sail vault or pendentive dome, which springs directly from the four corners.

Where it appears in the book

In the chapters What Is Architecture?, Post and Lintel, Walls and Openings, Vaults, Domes, The Roof, Frame and Skin, The Ancient World.

A feature of Aegean Bronze Age, Ancient Roman, Byzantine, Hindu Temple: Dravida (South Indian), Early Islamic (Umayyad and Abbasid), Moorish (Western Islamic), Russian, Persian Islamic (Seljuk, Timurid and Safavid), Ottoman, Renaissance architecture.

Nearby in the glossary

Diminution · Dipteral · Dolmen · Dom-ino · Domus · Doric · Dormer · Dou