Ellipse definition |Dictionary.com

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Ellipse

8 dictionary results for: Ellipse

Dictionary.com Unabridged (v 1.1) - Cite This Source - Share This

el·lipse

[i-lips] Pronunciation Key

–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.

[Origin: 1745–55; < F < L ellīpsis ellipsis; or by back formation from the pl. ellipses

]

Dictionary.com Unabridged (v 1.1)
Based on the Random House Unabridged Dictionary, © Random House, Inc. 2006.

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American Heritage Dictionary - Cite This Source - Share This

el·lipse (ĭ-lĭps') Pronunciation Key

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n.

A plane curve, especially:
1. A conic section whose plane is not parallel to the axis, base, or generatrix of the intersected cone.
2. The locus of points for which the sum of the distances from each point to two fixed points is equal.
Ellipsis.

[French, from Latin ellīpsis, from Greek elleipsis, a falling short, ellipse, from elleipein, to fall short (from the relationship between the line joining the vertices of a conic and the line through the focus and parallel to the directrix of a conic) : en-, in; see en-² + leipein, to leave; see leik^w- in Indo-European roots.]

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The American Heritage® Dictionary of the English Language, Fourth Edition
Copyright © 2006 by Houghton Mifflin Company.
Published by Houghton Mifflin Company. All rights reserved.

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Online Etymology Dictionary - Cite This Source - Share This
ellipse

1656 (implied in ellpitical), from Fr. ellipse, from L. ellipsis "ellipse," also, "a falling short, deficit," from Gk. elleipsis (see ellipse), 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.).

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WordNet - Cite This Source - Share This

ellipse
noun
a closed plane curve resulting from the intersection of a circular cone and a plane cutting completely through it; "the sums of the distances from the foci to any point on an ellipse is constant"

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The American Heritage Science Dictionary - Cite This Source - Share This

ellipse (ĭ-lĭps') Pronunciation Key
A closed, symmetric curve shaped like an oval, which can be formed by intersecting a cone with a plane that is not parallel or perpendicular to the cone's base. The sum of the distances of any point on an ellipse from two fixed points (called the foci) remains constant no matter where the point is on the curve.

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American Heritage New Dictionary of Cultural Literacy, Third Edition - Cite This Source - Share This
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 orbits of the planets and of many comets are ellipses.

[Chapter:] Physical Sciences and Mathematics

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Webster's Revised Unabridged Dictionary - Cite This Source - Share This

Ellipse

El*lipse"\, n. [Gr. ?, prop., a defect, the inclination of the ellipse to the base of the cone being in defect when compared with that of the side to the base: cf. F. ellipse. See Ellipsis.]

1. (Geom.) An oval or oblong figure, bounded by a regular curve, which corresponds to an oblique projection of a circle, or an oblique section of a cone through its opposite sides. The greatest diameter of the ellipse is the major axis, and the least diameter is the minor axis. See Conic section, under Conic, and cf. Focus.

2. (Gram.) Omission. See Ellipsis.

3. The elliptical orbit of a planet.

The Sun flies forward to his brother Sun; The dark Earth follows wheeled in her ellipse. --Tennyson.

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