This universe can be different in a few ways, such as AR (Alternate Reality), AT (Alternate Timeline), or AH (All Human).
The last applies to fantasy or science fiction stories which have non-human characters.
Canon (derived from the term's usage in the Christian religion and popularized in this context by the Baker Street Irregulars) refers to the "official" source material upon which fan fiction can be based.
In recent years, some fandoms have engaged in lengthy debate over what is or is not "canon", usually due to multiple writers in various media creating contradictory source material, such as in metaseries like Doctor Who or Buffy the Vampire Slayer.
It is important to note that something that is regarded as "canon" is regarded as being essentially a verifiable fact in the given fandom.
Details as complex as the laws of physics in a given story universe or as minute as how a character's name is meant to be spelled can be referred to as "canon" details, so long as they are specifically shown or otherwise directly revealed in the source material; this includes character behavior as well, though debate over what can or cannot be considered "canon behavior" is often a point of contention in fandom.
Usually in such cases the characters retain their names and personality, despite the change in species.
Fanzine A collection of fan fiction produced as a magazine, either in print (printzine) or online (webzine).
In the event that a term fits under more than one subject, it has been defined in its first occurrence on this page, and referred back to in any further occurrences.
A handful of key terms are applied cross-fandom and related to fan fiction norms.
In fan fiction communities, especially online, generally fandom refers to people who enjoy a specific story, character, game, etc., and actively interact with others; that is, a group of (however scattered) individuals who share interest in the same media.
The term also sees occasional use as a synonym for the canon work.
A story can also be termed AU when the author makes major changes to the canonical storyline or premise, such as killing off a major character, changing characters' motives or alliances, annulling major events or changing the setting.