Glossary
- Obelisk
- Lofty pillar of square section, tapering at the top and ending pyramidically.
- Octostyle
- Of a porch or portico: with eight columns across the front.
Harvey Lonsdale Elmes,
1841-56 - Oculus
- Circular opening.
- Oeil de boeuf
- Small oval window, set horizontally. Also called a bullseye window.
- Ogee
- A double curve, bending first one way and then the other. An ogee or ogival arch, especially popular in the 14th century, is pointed at the top. A nodding ogee curves forward from the wall face at the top.
- Old English
- A style used from c. 1860, in which tile-hanging, tall chimneys, half-timbering and other details of the gabled vernacular architecture of south-east England are picturesquely combined.
- Open pediment
- A pediment with the centre of the base omitted.
- Open string
- A sloping member of a staircase covering the ends of the treads and risers and cut into their shape; hence an open-string staircase. Compare closed string.
- Opus sectile
- Decorative mosaic-like facing.
- Opus signinum
- Composition flooring of Roman origin.
