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retrodirective

American  
[re-troh-di-rek-tiv, -dahy-] / ˌrɛ troʊ dɪˈrɛk tɪv, -daɪ- /

adjective

Optics.
  1. (of a mirror, reflector, etc.) having three reflecting surfaces so oriented that a ray of light is reflected in a direction parallel but opposite to its original direction.


Etymology

Origin of retrodirective

retro- + directive