A circle is a shape consisting of a curved line completely surrounding an area. Every part of the line is the same distance from the centre of the area.

A circle of something is a round flat piece or area of it.

A circle of objects or people is a group of them arranged in the shape of a circle.

If something circles an object or a place, or circles around it, it forms a circle around it.

If an aircraft or a bird circles or circles something, it moves round in a circle in the air.

To circle around someone or something, or to circle them, means to move around them.

If you circle something on a piece of paper, you draw a circle around it.

You can refer to a group of people as a circle when they meet each other regularly because they are friends or because they belong to the same profession or share the same interests.

In a theatre or cinema, the circle is an area of seats on the upper floor.

If you say that you have come full circle or have turned full circle, you mean that after a long series of events or changes the same situation that you started with still exists.

If you say that someone is going round in circles or around in circles, you mean that they are not achieving anything because they keep coming back to the same point or problem.