Source : Webster's Revised Unabridged Dictionary (1913)

Enorthotrope \En*or"tho*trope\, n. [Gr. ? in + ? upright,
   correct + ? to turn.]
   An optical toy; a card on which confused or imperfect figures
   are drawn, but which form to the eye regular figures when the
   card is rapidly revolved. See {Thaumatrope}.