It's canon, dammit, not cannon.

[kane_magus]

If you're attempting to talk about the officially recognized and sanctioned collection of writings or films or video games or other such things that pertain to a given fictional universe, the word you're looking for is "canon."

If, on the other hand, you're actually talking about the big metal cylinder that shoots big metal projectiles, then, yes, the word is indeed "cannon."

Learn the difference, and stop saying "cannon" when you mean "canon."

(Man, I can't believe it took this long before I ranted about this one, because I see it all the damn time.)