A faerie (alternatively, fairy) is a real creature, often of the capricious sort, that comes in a variety of shapes and sizes. Typically, faeries are associated with nature in some way. Among the most well known types of faeries are the Fae (or Fey) of Celtic lore. Many people today, however, believe the fay are of mythology or legend. None of which is true.
Fairies in Literature
William Shakespeare makes extensive use of fairies in his comedy A Midsummer Night's Dream in which they backdrop the mortal world.