The term canon, or canonicity, describes the rules of what is presented as true and what has happened within an imaginary world. Even though the idea of canonicity might seem strange given that it deals with the imaginary, the concept highlights the audience's desire for authenticity and consistency (Proctor, 2017).
Andres summarizes in her article on Transmedia Storytelling in the Marvel Universe how Parrish (2007) describes 'canon' as the material that is considered 'official' in a fictional universe. Parrish contrasts this to works of fan fiction, which are considered 'non-canon' as they do not decide what is true within that imaginary world. This proposes two meanings of 'canon': The first "refers to the overall set of storylines, premises, settings, and characters offered by the source media text" (Parrish, 2007). The second meaning considers canon as "a descriptor of specific incidents, relationships, or story arcs that take place within the overall canon" (Parrish, 2007). This implies that some incidents and/or relationships can be referred to as 'canon' or 'non-canon'.
Andres, P. C. (2021). The Power of Transmedia Storytelling in the Marvel Cinematic Universe. Diggit Magazine.
Parrish, J. (2007). Inventing a Universe: Reading and Writing Internet Fan Fiction (Doctoral Dissertation).
Proctor, W. (2017). Canonicity, In M.J.P., Wolf (Ed.). The Routledge Companion to Imaginary Worlds (ed., pp. 236-245). New York: Routledge.