For the real world page, please see Star Trek fan fiction.
Fan fiction was a work of fiction that was written by a fan of a certain subject. In particular, it referred to unofficial works patterned after or utilizing characters, settings, and details from previously written popular works, such as books, movies, television programs, et cetera, written by someone who enjoyed the work in question.
In 2381, onboard the USS Cerritos, Ensign Beckett Mariner referred to the setup of fellow ensign Brad Boimler's holodeck program as bad fan fiction. (LD: "Crisis Point 2: Paradoxus")

Boimler as he learned that Tendi found his secret fan fiction