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
Recent Examples on the Web
In its heyday, Aqua flew around 438 miles (705 kilometers) above the surface of the Earth, moving from the North Pole to the South Pole in an ellipse 14 times a day, scanning the entire planet.
—
Tom Brown,
Space.com,
20 May 2026
That ellipse pattern can be seen across the door panels also, and, in another first for the marque, the graphic covers both the door panel face and the armrest area.
—
Nicole Hoey,
Robb Report,
1 May 2026
This resonance dramatically stretches the planet’s orbit, turning it into a long, narrow ellipse.
—
Rupendra Brahambhatt,
Interesting Engineering,
31 Jan. 2026
The double-ellipse frame now reveals the full architecture of the caliber DR002SR, while the watch preserves the classical proportions and architecture of the original.
—
Luisa Zargani,
Footwear News,
19 Jan. 2026
See All Example Sentences for ellipse
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Tom Brown,
Space.com,
20 May 2026
That ellipse pattern can be seen across the door panels also, and, in another first for the marque, the graphic covers both the door panel face and the armrest area.
—
Nicole Hoey,
Robb Report,
1 May 2026
This resonance dramatically stretches the planet’s orbit, turning it into a long, narrow ellipse.
—
Rupendra Brahambhatt,
Interesting Engineering,
31 Jan. 2026
The double-ellipse frame now reveals the full architecture of the caliber DR002SR, while the watch preserves the classical proportions and architecture of the original.
—
Luisa Zargani,
Footwear News,
19 Jan. 2026
See All Example Sentences for ellipse
Cite this Entry
“Ellipse.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/ellipse. Accessed 6 Jul. 2026.
Copy CitationKids Definition
ellipse
noun
el·lipse
i-ˈlips 
e-
: an oval shape that is a conic section
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