ellipse

noun
el·lipse | \i-ˈlips, e-\

Definition of ellipse 

1a : oval

b : a closed plane curve generated by a point moving in such a way that the sums of its distances from two fixed points is a constant : a plane section of a right circular cone that is a closed curve

2 : ellipsis

Illustration of ellipse

Illustration of ellipse

ellipse 1b: F, F' foci; P, P', P'' any point on the curve; FP + PF' = FP'' + P''F' = FP' + P'F'

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The Property of an Ellipse

A closed curve consisting of points whose distances from each of two fixed points (foci) all add up to the same value is an ellipse. The midpoint between the foci is the center. One property of an ellipse is that the reflection off its boundary of a line from one focus will pass through the other. As a result, in an elliptical room, a person whispering at one focus is easily heard by someone at the other. An oval may or may not fit the definition of an ellipse.

Examples of ellipse in a Sentence

Recent Examples on the Web

Imagine seeing a tiny sliver of a line and being asked to draw the ellipse that line was a part of — that was the mathematical challenge. Brian Resnick, Vox, "How Johann Carl Friedrich Gauss rediscovered a lost dwarf planet," 30 Apr. 2018 The designers at Hargreaves, Mary Margaret Jones and Brett Seamans, describe their composition as two interlocking squares, bisected by an ellipse. Inga Saffron, Philly.com, "Love Park was supposed to be the People's Park. How did it end up as a granite Sahara?," 26 Apr. 2018 The space telescope will fly in a large ellipse that takes it out beyond the moon and then in close to the Earth to downlink its data. Jay Bennett, Popular Mechanics, "SpaceX Successfully Launches TESS Space Telescope (Updated)," 18 Apr. 2018 It is laid out as a geometric ellipse, according to a study by mathematician Clark Kimberling, a professor at the University of Evansville. Martin Weil, Washington Post, "Moon will be putting on a show early Wednesday," 29 Jan. 2018 Instead, the moon traces out a geometric figure known as an ellipse. Martin Weil, Washington Post, "Moon will be putting on a show early Wednesday," 29 Jan. 2018 That’s because the moon’s orbit around the Earth is an ellipse, not a circle. Jeffrey Kluger, Time, "The Beauty and Science of a Total Solar Eclipse," 18 Aug. 2017 Things about angles, ellipses, gravity, probability, magnetics, pop culture, history. Angela Hill, star-telegram, "Pinball as science? It’s game on in California," 25 July 2017 That's because the moon's orbit is not a perfect circle, but rather is an ellipse — which means the moon's distance from Earth ranges from a low of about 220,000 miles (354,000 km) to a high of about 250,000 miles (402,000 km). Time, "Why Total Solar Eclipses Are So Rare," 6 July 2017

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'ellipse.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of ellipse

circa 1753, in the meaning defined at sense 1a

History and Etymology for ellipse

Greek elleipsis

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Time Traveler for ellipse

The first known use of ellipse was circa 1753

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More Definitions for ellipse

ellipse

noun

English Language Learners Definition of ellipse

: a shape that resembles a flattened circle

ellipse

noun
el·lipse | \i-ˈlips \

Kids Definition of ellipse

: a shape that looks like a flattened circle

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