A circle is a simple closed shape in geometry that is defined as the set of all points in a plane that are equidistant from a fixed point, known as the center of the circle.

 The distance from the center to any point on the circle is known as the radius of the circle, and the distance across the circle passing through the center is known as the diameter. The circle is a fundamental shape in geometry and has many important properties, such as its circumference, area, and chord length. Circles are used in many fields, including mathematics, engineering, and physics, and are also commonly used in everyday life, such as in the design of wheels, clocks, and other circular objects.