Thau"ma*trope (?), n. [Gr. a wonder + to turn.] Opt.
An optical instrument or toy for showing the persistence of an impression upon the eyes after the luminous object is withdrawn.
⇒ 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 rapidly '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.
© Webster 1913.