A fantasy world or fictional world is a world created for fictional media, such as literature, film or games. Typical fantasy worlds feature magical abilities. Some worlds may be a parallel world connected to Earth via magical portals or items ; an imaginary universe hidden within ours ; a fictional Earth set in the remote past or future ; an alternative version of our History ; or an entirely independent world set in another part of the universe.

Middle-earth is the setting of much of the English writer J. R. R. Tolkien's fantasy. The term is equivalent to the Miðgarðr of Norse mythology and Middangeard in Old English works, including Beowulf. Middle-earth is the human-inhabited world, that is, the central continent of the Earth, in Tolkien's imagined mythological past. Tolkien's most widely read works, The Hobbit and The Lord of the Rings, are set entirely in Middle-earth. "Middle-earth" has also become a short-hand term for Tolkien's legendarium, his large body of fantasy writings, and for the entirety of his fictional world.