ellipse

/ɪˈlɪps/

/ɪˈlɪps/

An ellipse is a closed-plane curve that results from the intersection of a plane cutting through a cone. In other words, it’s an oval.

This is a word you'll probably see in geometry class, though it's a shape you can find all over the place. An ellipse is a closed curve that never made it around to a circle. If one thing travels around another in the shape of an ellipse — like the earth around the sun — it has an elliptical orbit. The plural for both ellipse and ellipsis is ellipses — so be careful not to mix up your ovals with your dots.

Definitions of ellipse

1. 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”

   synonyms: oval

   types:

   circle

   ellipse in which the two axes are of equal length; a plane curve generated by one point moving at a constant distance from a fixed point

   circle of curvature, osculating circle

   the circle that touches a curve (on the concave side) and whose radius is the radius of curvature

   circlet

   a small circle

   equator

   a circle dividing a sphere or other surface into two usually equal and symmetrical parts

   epicycle

   a circle that rolls around (inside or outside) another circle; generates an epicycloid or hypocycloid

   type of:

   conic, conic section

   (geometry) a curve generated by the intersection of a plane and a circular cone