The definition comes from the movie (Spider-Man: Across the Spider-Verse) it is an inevitable event or action good or bad that is supposed to happen that results your future self.
for example a Canon event can be the the time where peter parker became Spider-man because he got bit by a mutated spider and that his uncle got murdered by a burglar which in result made him want to do justice and become a superhero
An event in someone's life that must happen, in order to keep the balance of the multiverse and a development in their storyline. If you happen to change or distrupt it, the multiverse will collapse.
"Hey, i saw Jhon's girl with another man! should we tell him?"
A sunburn or suntan focused on the left arm. It is caused by the left side of the body being the only half that gets exposed to sunlight while driving. Presumably, it would be located on the right side of the body in countries where they drive on the left side of the road.
British slang for a scientist or technical expert, esp . when the speaker is not certain of the expert’s specific field of study. Not necessarily derogatory, but typically used by persons without a technical background. In the US, the equivalent would be “egghead”, “squint”, or “geek.”
Origin of the word is unknown. Started sometime in World War 2. Given the typical evolution of British slang, could easily have started because what these experts did was confusing or “baffling” to the common person.