Ogee arch

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.

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.

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 arc flowing into a 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.

The cyma reversa form occurs in antiquity. For example, in ancient Persia, the Tomb of Cyrus featured the cyma reversa. The cyma reversa is also evident in ancient Greek architecture. The ogee shape is one of the characteristics of the Gothic style of architecture, especially decorative elements in the 14th and 15th century late Gothic styles called Flamboyant in France and Decorated in England. Ogee windows and arches were introduced to European cities from the Middle East. The ogee curve is an analogue of a "cyma curve", the difference being that a cyma has horizontal rather than vertical ends.

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