Junior high school mathematics knowledge points-geometry, two definitions of angle 1, two definitions of angle, one is a graph composed of two rays with the same endpoint called angle. To understand the two key points in the definition, ① an angle is a graph composed of two rays, ② these two rays must have the same endpoint. The other is a pattern formed by light rotating from one direction to another around the endpoint. As you can see, the initial light and the last light form an angle. 2. Definition of angular bisector. A ray divides an angle into two equal angles. This ray is called the bisector of this angle.