The measure of the amount by which a figure is rotated about a point of rotation.
This measure is negative for a clockwise rotation and positive for a counterclockwise rotation.
An angle of rotation can be expressed using various measurement systems such as the sexagesimal system (in degrees, minutes and seconds) and the circular system (in radians) or by using numbers or fractions of turns.
Example
In this figure, the letter a indicates the measure of the rotation.