Meaning of ANGLE in English
In geometry, a pair of rays (see line ) sharing a common endpoint (the vertex).
An angle may be thought of as the rotation of a single ray from an initial to a terminal position. Clockwise rotation is considered negative and counterclockwise rotation positive. Either may be measured in degrees (one full rotation = 360k) or radians (one full rotation = 2π rad). A 90k angle is called a right angle. Any angle less than 90k is an acute angle. Any angle more than 90k but less than 180k is an obtuse angle.
Britannica English dictionary. Английский словарь Британика. 2012