The bending of a wave, such as light or sound, as it passes from one medium to another with different density.
The refraction of light in water causes objects submerged in it to appear bent or distorted.
The determination of the refractive characteristics of the eye, typically performed to establish the correct prescription for eyeglasses or contact lenses.
During the eye exam, the optometrist carried out a refraction to find his updated lens prescription.