Just came across a paragraph in Wikipedia’s disambiguation page for the word “canon” that includes a few terms I’ve never heard before:

In fiction, the officially authorized interpretation of characters and events. In fandom, the term is often used to distinguish between “canonical” accounts (i.e. those authorized by the copyright holder) and those of fanfiction, sometimes called fanon. In serial fiction, new material can contradict earlier material (a practice known as retconning), in which case the new material becomes canon. Publishers, especially in mainstream comic books, sometimes release “what-if” stories featuring non-canonical interpretations of their characters.

Here is the beginning of their entry on “fanon:”

Fanon is a fact or ongoing situation in fan fiction stories related to a television program, book, movie, or video game that has been used so much by fan writers that it has been more or less established as having happened in the fictional world, but it has not actually been established as having happened on the show, book or movie itself. Fanon is a portmanteau word of fan and canon.

This next one is a real bombshell, and if it doesn’t show the obvious parallels between religion and science fiction, then I don’t know what the hell does:

A variation of fanon is “personal canon”, which is a set of “fanon”-like facts that are accepted as canon by an individual fan or a group of fans. Proponents of “fanon” or “personal canon” have been known to be offended when these terms are used, as “fanon” facts have often become better accepted than canon. This is widespread among Star Trek fans; for example, the prequel TV series Star Trek: Enterprise is rejected by many Trekkers on the basis that it violates “fanon” regarding the history of the Federation (rather than canon facts seen on earlier series). Similarly, some Trek fans have also seen fit to reject and “decanonize” individual episodes or films that don’t fit with their vision of the Star Trek universe (or, alternately, the perceived vision of the late Star Trek creator, Gene Roddenberry). Some consider such a selective view elitism, or simply an egotistical way to label stories one simply didn’t like very much.

They also have a really interesting list of “fanonical” items which are commonly accepted as truth of fans of various tv shows and other series. Worth checking out if you’re into that sorta shit. One of my favorites is that it’s popularly accepted that KITT, from Knight Rider is supposed to have been built around an android Cylon brain (from Battlestar Galactica) that crash-landed on earth in 1980. That’s fucking incredible.

Also, there is an entry on “retconning” which states:

Retroactive continuity – commonly contracted to the portmanteau word retcon – refers to the act of changing previously established details of a fictional setting, often without providing an explanation for the changes within the context of that setting.

That definitely also happens within the history of religions also, although I guess it’s ultimately just a nerdly word to describe historical revisionism.

This is a topic area I’m extremely interested in, and I have a few other posts which deal with the topic in various ways, for anyone who is interested:

1. Version Control
2. Canon, Apocrypha & Centralized Distribution
3. Contemporary Apocryphal Culture
4. Fan-Fiction as apocrypha
5. Mods