Glossary · O
Oculus
Also called oculi
A circular opening, especially the open “eye” at the crown of a dome, as in the Pantheon, where it is some 8.2 m across and the only source of light. Also a round window.
Rules that use the word
The rose: a window turned about its centre. Design a rose by dividing the circle into equal sectors; fill each with the same traceried unit (a light with a cusped pointed head, an oculus above) radiating from a central hub, so that the whole is generated from one sector by rotation.
Where it appears in the book
In the chapters Walls and Openings, Domes, Romanesque and Gothic.
Nearby in the glossary
Nosing · Noyane · Nymphaeum · Obelisk · Ogee · Ondol · Onion dome · Open plan