The angle of reflection measures the angle at which reflected light bounces off a surface.

- The angle of reflection is measured between a ray of light which has been reflected off a surface and an imaginary line called the
*normal*. - In optics, the
*normal*is a line drawn on a ray diagram perpendicular to, so at a right angle to (90^{0}), to the boundary between two media. - If the boundary between the media is curved then the normal is drawn perpendicular to the boundary.