A rotary, sometimes nicknamed a traffic circle, is a type of intersection that directs both turning and through traffic onto a one-way circular roadway, usually built for the purposes of traffic calming or aesthetics. Contrary to a roundabout, where entering traffic always yields to traffic already in the circle and merges in directly, the entrances to traffic circles are 3-way intersections either controlled by stop signs, traffic signals, or not formally controlled. Colloquially, however, roundabouts are sometimes referred to as circles.