Aspects or material that are not officially part of the source material (of a work of fiction) but that fans promote or think could logically exist or occur in the source material. Also known as "fanon" and "head canon" (although the latter can also be applied to an individual fan's ideas, as opposed to those that have gained widespread currency). That pairing must be fan canon because I definitely don't remember seeing those two kiss in any episode of the series.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.