saucefactory:

Canon: What actually happened.

Headcanon: What you think happened, based on the characters, settings, storylines and all reasonable extrapolations thereof.

Heartcanon: What you feel ought to have happened, quite divorced from rationality or sense.

Soulcanon: What you know happened, deep down in your soul, regardless of what anyone says. Including the creators of canon, themselves.

Crotchcanon: What your gonads wish had happened, or, alternatively, what turns you on.