In 2000, Lucas Licensing appointed Leland Chee to create a continuity tracking database referred to as the “Holocron”.[5] As with every other aspect having to do with the overall story of Star Wars, the Holocron follows the canon policy that has been in effect for years.
The Holocron is divided into five levels (in order of precedence): G-canon, T-canon, C-canon, S-canon, and N-canon.
G-canon is George Lucas canon: Considered absolute canon, it includes Episodes I–VI (the most recently released versions) and the upcoming Episodes VII–IX feature films, the animated film Star Wars: The Clone Wars, and any statements by George Lucas (including unpublished production notes from him or his production department that are never seen by the public). Elements originating with Lucas in the scripts, filmed deleted scenes, movie novelizations, reference books, radio plays, and other primary sources are also G-canon when not in contradiction with the released films. G-canon overrides the lower levels of canon when there is a contradiction.
T-canon is Television canon:[6] refers to the canon level comprising only the two television shows: Star Wars: The Clone Wars and Star Wars Rebels. Its precedence over C-Level canon was confirmed by Chee.[7]
C-canon is Continuity canon: consisting of materials from the Expanded Universe including books, comics, and games bearing the label of Star Wars. Games and RPG sourcebooks are a special case; the stories and general background information are themselves fully C-canon, but the other elements such as character/item statistics and gameplay are, with few exceptions, N-canon.
S-canon is Secondary canon: covering the same medium as C-canon, it is immediately superseded by anything in higher levels of canon in any place where two elements contradict each other. The non-contradicting elements are still a canon part of the Star Wars universe. This includes all C-canon material released prior to April 25, 2014,[2] video games such as the online roleplaying game Star Wars: Galaxies, and certain elements of a few N-canon stories.
N-canon is Non-canon: “What-if” stories (such as stories published under the Star Wars: Infinities label), crossover appearances (such as the Star Wars character appearances in Soulcalibur IV), game statistics, and anything else directly contradicted by higher canon ends up here. N-canon is the only level that is not considered official canon by Lucasfilm. Any published material that contradicts things established in G-canon and T-canon is considered N-canon.
*head explodes*