When energy is transferred from 1 point to another traveling across a medium oscillating without ousting the medium makes waves.
<em>Wave fronts</em> are surfaces that merge points of the same phase in waves that travel across a medium. So when wave-fronts change their course at an interface and then returns to the medium which produced it we call it <em>Reflection</em>.
When light (which also travels in waves) hits a surface it bounces off, just like water waves, or sound, or any other type of energy traveling that way and changing direction it's called <em>reflection</em>.
