What does "thaumatrope" mean?

Thaumatrope: An optical instrument or toy for showing the presistence of an impression upon the eyes after the luminous object is withdrawn.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.