A shining or polished surface changes the direction of light.This change in direction is called reflection of light. Reflection is the change in direction of a wavefront at an interface between two different media so that the wavefront returns into the medium from which it originated.
Reflected waves are simply those waves that are neither transmitted nor absorbed, but are reflected from the surface of the medium they encounter. When a wave approaches a reflecting surface, such as a mirror, the wave that strikes the surface is called the incident wave, and the one that bounces back is called the reflected wave (refer to figure 2-4). An imaginary line perpendicular to the point at which the incident wave strikes the reflecting surface is called the normal, or the perpendicular. The angle between the incident wave and the normal is called the angle of incidence.
On the Reflecting media (like mirror) The angle between the reflected wave and the normal is called the angle of reflection.