the angle that a ray reflected from a surface makes with a line drawn perpendicular to this surface; it is equal to the angle of incidence (2).
angle of reflection
after a collision, the angle at which one object is moving relative to another (usually a stationary surface or environmental factor such as wind). Example: after a snooker ball has hit a cushion, the angle between the ball's direction of travel and the cushion. It is not necessarily the same size as the angle of incidence. Also known as angle of rebound.