refraction is the answer I got. All I did was search google for the definitions:
Reflection - the throwing back by a body or surface of light, heat, or sound without absorbing it.
Refraction - the fact or phenomenon of light, radio waves, etc., being deflected in passing obliquely through the interface between one medium and another or through a medium of varying density.
Example: change in direction of propagation of any wave as a result of its traveling at different speeds at different points along the wave front.
Diffraction - the process by which a beam of light or other system of waves is spread out as a result of passing through a narrow aperture or across an edge, typically accompanied by interference between the wave forms produced.
