Fanon is a slang term used especially on the Doctor Who Fanon Wiki that is an abbreviated form of fan-canon or fan fiction. The proper usage of the term refers to fan-created information that is generally accepted as canon but has not officially been made canon by BBC
For the purposes of Doctor Who Fanon, fanon encompasses all articles that do not directly relate to a work of fan fiction, fan fiction being short stories, novels, and the like. Fanon articles users write function as part of their own "fan repository," as they are part of their fanon continuity and only theirs—collaboration with other users not withstanding, though collaborations not directly relating to fan fiction works are still fanon. There are a variety of purposes for fanon ranging from a character outline for a role-playing game, an exercise in character development, or something as simple as a user wanting to share their ideas with other writers without having to write a fan fiction story to go along with it—among other possibilities. These types of articles encompass the majority of Doctor Who Fanon's pages.
Fanon can be used as a noun and as an adjective. A piece of material on this site is called fanon by itself, or can be called a "fanon article."