R1E1T1R1O1R1E1F4L1E1C3T1I1O1N1
20 points
RETROREFLECTION is validvalid
reflection of radiation back to its source regardless of incident angle [n]
the action or use of a retroreflector [n]
reflection of radiation back to its source regardless of incident angle [n]
the action or use of a retroreflector [n]