A circle is a round outline with no corners. Every point on that outline is the same distance from the center.

An uneven outline is different. Some parts bend farther outward and others curve inward, so it is not a perfect circle.

The straight segment from the center to the edge is called the radius. It connects the center to one point on the circle.

Follow the outline back to where you started. A circle is closed, round, and has no corners.