The dark circle within the cone is an ellipse.

- The definition of an ellipse is a path taken or a shape that results when a flat plane intersects a cone in a direction which is not parallel to the base of the cone.
An example of an ellipse are the rings of Saturn.

## ellipse

noun

*pl.*ellipses

Geom. the path of a point that moves so that the sum of its distances from two fixed points, the foci, is constant; closed curve formed by the section of a cone cut by a plane less steeply inclined than the side of the cone

Origin of ellipse

Modern Latin*ellipsis*; from Classical Greek

*elleipsis*, a defect, ellipse ; from

*elleipein*, to fall short ; from

*en-*, in +

*leipein*, to leave (see loan): so named from falling short of a perfect circle

## ellipse

noun

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

Origin of ellipse

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*in Indo-European roots.

^{w}-## ellipse

Noun

(*plural* ellipses)

Verb

(*third-person singular simple present* ellipses, *present participle* ellipsing, *simple past and past participle* ellipsed)

Origin

From French *ellipse*.