# Oval

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File:Oval1.PNG
This oval, with only one axis of symmetry, resembles a chicken egg.
File:Oval3.png
An oval with two axes of symmetry.

In geometry, an oval or ovoid (from Latin ovum, 'egg') is any curve resembling an egg or an ellipse. Unlike other curves, the term 'oval' is not well-defined and many distinct curves are commonly called ovals. These curves have in common that:

The word ovoidal refers to the characteristic of being an ovoid.

Other examples of ovals described elsewhere include:

## Egg shape

The shape of an egg is approximately that of half each a prolate (long) and roughly spherical (potentially even minorly oblate/short) ellipsoid joined at the equator, sharing a principal axis of rotational symmetry, as illustrated above. Although the term egg-shaped usually implies a lack of reflection symmetry across the equatorial plane, it may also refer to true prolate ellipsoids. It can also be used to describe the 2-dimensional figure that, revolved around its major axis, produces the 3-dimensional surface.

## Projective planes

In the theory of projective planes, oval is used to mean a set of q + 1 non-collinear points in PG(2,q), the projective plane over the finite field with q elements. See oval (projective plane).