Elliptical describes something shaped like an ellipse, which is an oval or flattened circle. Picture a circle that's been gently squeezed from two sides: that's an ellipse. The planets in our solar system follow elliptical orbits around the sun, not perfect circles as many people imagine. Earth's path through space is actually an ellipse, though it's so close to circular that you'd hardly notice the difference.

You might also encounter elliptical in describing a style of communication that leaves things out. When someone speaks in an elliptical way, they skip over words or ideas that listeners are expected to fill in themselves. If your friend says “Want to go?” instead of “Do you want to go to the park with me?”, that's elliptical speech. It works fine when everyone understands the missing parts, but it can confuse people who don't have the full context.

An elliptical trainer at the gym gets its name from the elliptical motion your feet make while using it: a smooth, oval-shaped path. This motion is easier on your knees than running because your feet never pound against a hard surface.