Ellipse (noun)

1. a closed plane curve consisting of all points at a fixed distance from two other points, the foci, such that the ratio of the distance between the foci to the distance between any point on the curve and the nearest focus is constant, 2. an oval shape, 3. a section of an orbit of a planet, comet, or satellite that is closest to the sun.

Origin:

Late 16th century: via latin from greek elleipsis "omission", from elleipein "leave out", from en- "in" + leipein "to leave".

Examples:

1. The path of a planet around the sun is an ellipse.
2. The shape of an egg is an ellipse.
3. An ellipse is defined by the two points that are the foci.
4. An ellipse is a type of conic section.
5. An ellipse can be defined by an equation.