A circle is a perfectly round, flat shape where every point on the edge is exactly the same distance from the center. If you tie a string to a pencil, hold the other end still on paper, and swing the pencil around while keeping the string tight, you'll draw a circle.

Circles appear everywhere in the world. Wheels are circular because that shape rolls smoothly. Plates are circles because they're easy to hold and use. The sun and moon look like circles in the sky (though they're actually spheres, which are three-dimensional shapes).

The word also describes a group of people connected by friendship or shared interests. Your circle of friends might include classmates you eat lunch with every day. A sewing circle brings together people who enjoy needlework. When you're part of someone's inner circle, you're one of their closest, most trusted friends.

To circle something means to draw a line around it, like when your teacher asks you to circle the correct answer. It can also mean to move in a circular path: hawks circle overhead while hunting, and runners circle a track.