# ellipse

[ih-lips]

### noun Geometry.

a plane curve such that the sums of the distances of each point in its periphery from two fixed points, the foci, are equal. It is a conic section formed by the intersection of a right circular cone by a plane that cuts the axis and the surface of the cone. Typical equation: (x2/a2) + (y2/b2) = 1. If a = b the ellipse is a circle.

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## RELATED WORDS

trajectory, rotation, pattern, path, arc, arch, contour, loop, apogee, track, curve, course, circle, locus, lap, round, cycle, perigee, swerve, sweep

## Nearby words

- ellicott city,
- ellington,
- ellington, duke,
- elliot's operation,
- elliott,
- ellipsis,
- ellipsograph,
- ellipsoid,
- ellipsoid of revolution,
- ellipsoidal

## Origin of ellipse

Dictionary.com Unabridged
Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

## Examples from the Web for ellipse

## ellipse

### noun

## Word Origin for ellipse

C18: back formation from ellipsis

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
© William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

## ellipse

1753, from French ellipse (17c.), from Latin ellipsis "ellipse," also, "a falling short, deficit," from Greek elleipsis (see ellipsis). So called because the conic section of the cutting plane makes a smaller angle with the base than does the side of the cone, hence, a "falling short." First applied by Apollonius of Perga (3c. B.C.E.).

Online Etymology Dictionary, © 2010 Douglas Harper

## ellipse

[ĭ-lĭps′]

The American Heritage® Science Dictionary
Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

## ellipse

[(i-lips)]

In geometry, a curve traced out by a point that is required to move so that the sum of its distances from two fixed points (called foci) remains constant. If the foci are identical with each other, the ellipse is a circle; if the two foci are distinct from each other, the ellipse looks like a squashed or elongated circle.

## Note

The New Dictionary of Cultural Literacy, Third Edition
Copyright © 2005 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.