Source : Webster's Revised Unabridged Dictionary (1913)

Thaumatrope \Thau"ma*trope\, n. [Gr. ? a wonder + ? to turn.]
   (Opt.)
   An optical instrument or toy for showing the presistence of
   an impression upon the eyes after the luminous object is
   withdrawn.

   Note: It consists of a card having on its opposite faces
         figures of two different objects, or halves of the same
         object, as a bird and a cage, which, when the card is
         whirled rapidlz round a diameter by the strings that
         hold it, appear to the eye combined in a single
         picture, as of a bird in its cage.