Source : Webster's Revised Unabridged Dictionary (1913)

Catoptrics \Ca*top"trics\, n. [Cf. F. catoptrique. See
   {Catropric}.] (Physics)
   That part of optics which explains the properties and
   phenomena of reflected light, and particularly that which is
   reflected from mirrors or polished bodies; -- formerly called
   {anacamptics}.

Source : WordNet®

catoptrics
     n : branch of optics dealing with formation of images by mirrors