When light travelling through one medium, falls on the surface of another medium, the following three effects may occur at the surface of separation of the two media: 

Reflection: A part of the incident light is bounced back into the first medium. This is called reflection of light. 

Refraction: Another part of incident light is transmitted into the second medium and diverges or bends from its path at the surface of separation. This is called refraction of light. 

Absorption: The remaining part of incident light is absorbed at the surface of separation. This is called absorption of light.