An ellipse is a special kind of oval that is mathematically regular, with two lines of symmetry. We usually think of it as looking like a "flattened" or "stretched" circle. Mathematically, a circle is a special case of an ellipse, where the minor (smallest diameter of ellipse) and major axis (largest diameter of ellipse) are equal. This is similar to how a square is a special case of a rectangle where all the sides have equal lengths. Below is an example of an ellipse.
Did you know?
The paths (orbits) of the planets around the sun are elliptical.
See also oval.
Related word elliptical.