A turn is 360° or 2π radians. The radian is a unit of plane Angle, equal to 180/ π degrees, or about 57 As an angular unit it is mainly useful for large angles, such as in connection with coils and rotating objects. In Geometry and Trigonometry, an angle (in full plane angle) is the figure formed by two rays sharing a common Endpoint, called A coil is a series of loops A coiled coil is a structure where the coil itself is in turn also looping A rotation is a movement of an object in a circular motion A two- Dimensional object rotates around a center (or point) of rotation See also winding number. The term winding number may also refer to the Rotation number of an Iterated map.
The British astronomer and science writer Sir Fred Hoyle (1915 - 2001) in Astronomy (London 1962), proposed dividing the circle, or turn into 1000 milliturns, with each milliturn corresponding to an angle of 21' 36", or less than half a degree. Sir Fred Hoyle FRS ( 24 June, 1915  &ndash 20 August, 2001) was an English Astronomer primarily Circles are simple Shapes of Euclidean geometry consisting of those points in a plane which are at a constant Distance, called the