Non-canonical

Non-canonical is the opposite of canon. Typically when something is non-canonical, it is not considered official in that particular fictional universe.

In other words, canonical events "actually occurred", whereas non-canonical events occur only in the non-canonical work itself. Non-canonical items include fan fiction and books not deemed canonical by the publisher, studio, or "the powers that be".

Other works can be quasi-canonical, like the Expanded Universe of Star Wars fame. While the events portrayed in EU stories are not expressed acknowledged in the films, the powers that be at Lucasfilm do acknowledge their existence in the over-all universe of Star Wars (they only become non-canonical when a new canonical item, such as a new prequel movie, directly contradicts something in the EU).