Angular displacement

The angular displacement (symbol θ, ϑ, or φ) – also called angle of rotation, rotational displacement, or rotary displacement – of a physical body is the angle (with the unitradian, degree, turn, etc.) through which the body has rotated (revolved or spun) around a centre of rotation or axis of rotation. Angular displacement may be signed, indicating the direction of rotation (e.g., clockwise versus counterclockwise); it may also be greater (in absolute value) than a full turn if the rotation was.