ENIGMA , a riddle or puzzle, especially a form of verse or prose composition in which the answer is concealed by means of metaphors. Such were the famous riddle of the Sphinx and the riddling answers of the ancient oracles. The composition of enigmas was a favourite amusement in Greece and prizes were often given at banquets for the best solution of them (Athen. x. 457). In France during the 17th century enigma-making became fashionable. Boileau, Charles Rivière Dufresny and J.J. Rousseau did not consider it beneath their literary dignity. In 1646 the abbé Charles Cotier (1604-1682) published a Recueil des énigmes de ce temps. The word is applied figuratively to anything inexplicable or difficult of understanding.
Note - this article incorporates content from Encyclopaedia Britannica, Eleventh Edition, (1910-1911)