turning circle

Short definition from Wiktionary

Noun

1. 1
   The circular path formed by the wheel furthest from the centre of the turn when turning to the maximum extent.
2. 2
   The path followed by a vessel’s center of gravity when it makes a complete turn of 360° with a consistent rudder angle. (FM 55-501)
3. 3
   A place where a vehicle can turn and face in the opposite direction.