Does it mean "as it relates to the original source"? The word drives me crazy. I have looked it up on google and it takes me to either the camera brand or cannons.
The term Canon in works of fiction refers to any 'authoritative' body of work related to said work of fiction.
In fiction, canon is the material accepted as part of the story in an individual universe of that story.
-Canon (fiction), Wikipedia
'Authoritative' can refer to any work which is approved or written specifically by the original author(s). This can include extra material such as:
- Video games
- Board games
- Director's Cuts and
- Behind the scenes
Any other works are considered to be works of Fan Fiction and not necessarily authorised by the original author(s).
For example, in the world created by George. R. R. Martin for his books series A Song of Ice and Fire the following works are considered canon:
- A Song of Ice and Fire
- The Tales of Dunk and Egg
- The World of Ice and Fire
- So Spake Martin - to a certain degree
There are some special cases; for example, A Song of Ice and Fire has a television adaptation (Game of Thrones - HBO) which is approved by the author (George R. R. Martin), but tends to deviate from the original storyline in the book(s).