Ogee

An ogee (/oʊˈdʒiː/ or /ˈoʊdʒiː/) is a curve (often used in moulding), shaped somewhat like an S, consisting of two arcs that curve in opposite senses, so that the ends are parallel. It is a kind of sigmoid curve.

The term has uses in architecture, mathematics, and fluid mechanics, as well as marine construction, clock design and plastic surgery.

Use in architecture

Ogee arch

In architecture, the principal use of the term is to describe an arch composed of two ogees, mirrored left-to-right and meeting at an apex. Ogee arches were a feature of English Gothic architecture in the later thirteenth century.

Moulding

A building's surface detailing (indoors or out) may have a moulding with an ogee-shaped profile, consisting (going from low to high) of a concave arc flowing into a convex arc, with vertical ends; if the lower curve is convex and higher one concave, this is known as a Roman ogee, although frequently the terms are used as if they are interchangeable and for a variety of other shapes. Alternative names for such a true Roman ogee moulding include cyma reversa and talon.