a circle formed by a plane that cuts a sphere not through its centre

(mathematics) The problem, proposed by ancient Greek geometers, of using a finite ruler-and-compass construction to make a square with the same area as a given circle.

An area in a field of crops where the stalks have been flattened into a circle or other geometric shape.

(netball) One of two semicircles in the goal thirds, radius 4.9 metres, in which the goal shooter and goal attack can shoot.

(geometry) A circle of radius 1. / (trigonometry, the unit circle) The circle of radius 1 with centre at the origin, used in defining trigonometric functions.

(sports, boxing, wrestling, professional wrestling) The boxing or wrestling ring.

(automotive, of a road vehicle) The circular path formed by the wheel furthest from the centre of the turn when turning to the maximum extent.

(soccer) The circle in the centre of the pitch which, at kick-off, the defending team may not enter until the attacking side has touched the ball.

(baseball) The circle drawn or painted on the field where the next batter to hit waits.

present participle of square the circle