A turn, from the Greek word τόρνος (tornos – a lathe), is a unit of angle measurement that is equal to 360°, 2π radians or τ (tau) radians. Turn is also referred to as a revolution or complete rotation or full circle or cycle or rev or rot. Turn can be subdivided into half turns, quarter turns, centiturns, milliturns, binary angles, points etc.
Turn is commonly used for planar rotations. Two special rotations have acquired appellations of their own: a rotation through 180° is commonly referred to as a half-turn (π radians), a rotation through 90° is referred to as a quarter-turn. A half-turn is often referred to as a reflection in a point since these are identical for transformations in two-dimensions.Read moreList of all Turn to other angle units individual converters.