reflection
[OED]: 2. a. The action, on the part of surfaces, of throwing back light or heat (rays, beams, etc.) falling upon them; the fact or phenomenon of light and heat being thrown back in this way. Also, the similar action of surfaces on other waves and radiations.
The return path of objects or waves (light, sound, water) that strike a surface and rebound; also a mirror image; a symmetry (q.v.) operation; a ricochet. A pattern of multiple reflections from thin films or small particles produces interference effects such as iridescence.
