An ellipse is a closed, curved shape that looks like a stretched or squished circle, characterized by two points called foci. Any point on the ellipse has a constant sum of distances to these two foci. The longest line passing through the center of the ellipse is the major axis, while the shorter line perpendicular to it is the minor axis. The degree of stretching or squishing determines the ellipse’s eccentricity, ranging from 0 (a perfect circle) to 1 (a highly elongated ellipse). Ellipses are found in various natural and man-made objects, including planetary orbits, certain optical instruments, and pizza oven domes.


An ellipse is a geometric shape defined as a closed curve with two distinct foci (plural of focus), where the sum of the distances from any point on the curve to the two foci remains constant. This unique characteristic of the ellipse makes it a fundamental shape in mathematics and science. The longest straight line passing through the center of the ellipse is known as the major axis, and the perpendicular line that intersects it at the center is called the minor axis. The major axis is longer than the minor axis, which gives the ellipse its characteristic stretched or squished appearance. Ellipses appear in various natural phenomena and engineering applications, such as the orbits of planets around the sun, the shapes of certain lenses and mirrors, and the design of satellite dish reflectors.

One essential parameter describing an ellipse is its eccentricity, which is a measure of how stretched or squished it is. Eccentricity ranges from 0 (for a perfect circle) to 1 (for a highly elongated ellipse). The closer the eccentricity is to 0, the more the ellipse resembles a circle. The mathematical properties and symmetrical nature of ellipses make them a valuable tool in various fields, from astronomy to engineering and design, where their precise geometric properties are applied to solve problems and optimize designs.