The traffic circle is a circular intersection where road traffic moves anticlockwise in one direction around a central island. You have the first right of way when you are present already within a traffic circle. But if you are entering a traffic circle then you must yield the right of way to the vehicles already preset inside the traffic circle.
It is a modern form of intersection designed to improve road safety. The traffic moves slowly enough in the circle, which is also safe for pedestrian crossing. Compared to stop signs and traffic signals intersections, traffic circles improve traffic flow and reduce the risk of traffic collisions.