Cāt'a-di-ōp'trie or Cāt'a-di-ōp'trie-al, a.

a. [From Gr. κατά, against, and διοπτρικός, belonging to the use of the διόπτρα, from διόπτη, a spy, from διά, through, and ὄπτειν, to see, to look; Fr. catadioptrique.] Pertaining to or involving both the reflection and refraction of light; as, a catadioptric telescope. Hutton.