- verb to cause a wave, such as light or sound, to change direction or turn as it passes from one medium into another of different density
- To deflect light via refraction.
- verb to alter the course of a wave of energy that passes into something from another medium, such as light through a refracting lens
- verb to measure the degree of refraction in a lens or eye
- verb to make light rays change direction as they go from one medium such as air to another such as water at an angle