Answer: reflector

AnswerCrossword Clue
REFLECTORType of telescope
reflectorsomething or someone that reflects
reflectorA piece of glass, metal, or other material for reflecting light in a required direction, e.g., a red one on the back of a motor vehicle or bicycle
reflectorAn object or device that reflects radio waves, seismic vibrations, sound, or other waves
reflectorA reflecting telescope