Illustration of ellipse
- F F' foci
- P P' P'' any point on the curve
- FP + PF' = FP'' + P''F' = FP' + P'F'
1
a
: 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
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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
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As an actor who’s appeared on several hit shows, Johnston was identified quickly among the hundreds of Donald Trump supporters who stormed the Capitol following an inflammatory speech by the outgoing president at the nearby ellipse.
—
Kevin Dolak, The Hollywood Reporter, 29 Oct. 2024
Since the moon’s orbital path around Earth is a slight ellipse, there’s a near-point (perigee) and a far-point (apogee) every month.
—Jamie Carter, Forbes, 18 Oct. 2024
That’s because the moon’s orbital path around Earth is a slight ellipse, so there’s always a near-point (perigee) and a far-point (apogee) every month.
—Jamie Carter, Forbes, 16 Aug. 2024
Right now Bennu is 89 percent as far from the sun as Earth is, but to rendezvous with Earth, the spacecraft will have to follow an ellipse that takes it 40 percent farther out—almost as far from the sun as Mars is.
—IEEE Spectrum, 7 May 2021
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Kevin Dolak, The Hollywood Reporter, 29 Oct. 2024
Since the moon’s orbital path around Earth is a slight ellipse, there’s a near-point (perigee) and a far-point (apogee) every month.
—Jamie Carter, Forbes, 18 Oct. 2024
That’s because the moon’s orbital path around Earth is a slight ellipse, so there’s always a near-point (perigee) and a far-point (apogee) every month.
—Jamie Carter, Forbes, 16 Aug. 2024
Right now Bennu is 89 percent as far from the sun as Earth is, but to rendezvous with Earth, the spacecraft will have to follow an ellipse that takes it 40 percent farther out—almost as far from the sun as Mars is.
—IEEE Spectrum, 7 May 2021
See all Example Sentences for ellipse
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Cite this Entry
“Ellipse.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/ellipse. Accessed 21 Dec. 2024.
Copy CitationKids Definition
ellipse
noun
el·lipse
i-ˈlips 
e-
: an oval shape that is a conic section
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