**The formal term for an elongated circle or oval is an ellipse.** An ellipse resembles a squished circle that consists of one curved line, but it does not have a constant radius.

While an ellipse is a specific shape, a circle meets all the conditions to also be considered an ellipse. For a shape to be an ellipse, it must have foci. Foci are two points in an ellipse that are central to the shape. When any point on the ellipse is chosen, the sum of the distance from each foci to the point on the ellipse will always be the same.