The phenomenon of bending of light rays when passed from one medium to another medium of different optical density is known as refraction!!!IN CASE YOU DONT KNOW WHAT IS OPTICAL DENSITY!-liquids can be identified as rarer or denser by means of mass per unit volume but in case of solids a different term is used known as optical density !! Which is determined by the intensity of deviation of light rays when passed through it!!! HOPE IT HELPS??
The phenomenon of bending of light on passing from one medium to another is called refraction
A ray of light come from one medium in rair and go in another medium in danser