Reflector

Noun

 * 1) Something which reflects heat, light or sound, especially something having a reflecting surface.
 * 2) A reflecting telescope.
 * 3) A small, often red, reflecting disk on the rear of a vehicle that reflects the headlights of other vehicles.

Thesaurus
Cassegrainian telescope, Newtonian telescope, OAO, OSO, astronomical observatory, astronomical telescope, cheval glass, coelostat, concave mirror, convex mirror, coronagraph, coronograph, distorting mirror, glass, hand mirror, heliostat, looking glass, mirror, observatory, orrery, pier glass, planetarium, radar telescope, radio observatory, radio telescope, rear-view mirror, refractor, seeing glass, shaving mirror, spectrograph, spectroheliograph, spectrohelioscope, spectroscope, speculum, telescope, window mirror

Noun
reflector


 * 1) reflecting device on the back of a vehicle, e.g. a bike