Refraction

The bending of light that occurs at the interface between two transparent media. It occurs when the speed of light changes.

Angle of Refraction

The angle at which a refracted ray of energy leaves the interface at which the refraction occurred, measured between the direction of the refracted ray and perpendicular to the interface at the point of refraction.

See also: Diffraction, Diffuse Reflection, Refractive Index.