The Collaborative International Dictionary of English v.0.48:

Reflector \Re*flect"or\ (-[~e]r), n. [Cf. F. r['e]flecteur.]
   1. One who, or that which, reflects. --Boyle.
      [1913 Webster]

   2. (Physics)
      (a) Something having a polished surface for reflecting
          light or heat, as a mirror, a speculum, etc.
      (b) A reflecting telescope.
      (c) A device for reflecting sound.
          [1913 Webster]

WordNet (r) 3.0 (2006):

reflector
    n 1: device that reflects radiation
    2: optical telescope consisting of a large concave mirror that
       produces an image that is magnified by the eyepiece; "Isaac
       Newton invented the reflecting telescope in 1668" [syn:
       reflecting telescope, reflector]

Moby Thesaurus II by Grady Ward, 1.0:

36 Moby Thesaurus words for "reflector":
   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