a. imagination unrestricted by reality

b. (as modifier): a fantasy world
2. a creation of the imagination, esp a weird or bizarre one
3. psychol
a. a series of pleasing mental images, usually serving to fulfil a need not gratified in reality
b. the activity of forming such images
4. a whimsical or far-fetched notion
5. an illusion, hallucination, or phantom
6. a highly elaborate imaginative design or creation
7. music

fantasia: fancy: another word for development

8. a. literature having a large fantasy content
b. a prose or dramatic composition of this type

(modifier) of or relating to a competition, often in a newspaper, in which a participant selects players for an imaginary ideal team, and points are awarded according to the actual performances of the chosen players: fantasy football

If your story falls under any of these definitions, under the "Add Category" section under a published page, add "Fantasy", and any subcategory.