# Circle

**Circle**, closed plane curve every point of which is at equal distance from a fixed point (center). A line segment between the center and the curve is called a *radius* (r); the word is also used for the length of that segment. A line segment whose 2 ends lie in the curve is a *chord*, and a chord passing through the center point is called the *diameter* (d). The distance around the edge is known as the *circumference* (C); C = πd. The area of a circle (A) is given by A = πr^{2}. The circle has been used to symbolize eternity, the universe, or heaven.

## Additional topics

21st Century Webster's Family Encyclopedia21st Century Webster's Family Encyclopedia - Children's literature to Clumber spaniel