catopter

/K AE1 T AA0 P T ER0/
noun
  1. 1

    A unit of measure of the converging power of a curved mirror, equal to the reciprocal of the focal length in meters; a diopter applied to a curved reflective surface as opposed to a lens.

  2. 2

    (obsolete) A reflecting optical glass or instrument; a mirror.

  3. 3

    An Ancient Greek anal dilator or speculum.