One of the best things about the Avatar universe is that one of our first introductions to the rules governing the world is "It's not magic, it's water bending," and then throughout the series it's revealed that actual ass magic also exists alongside the totally not magic bending.
angry spirit shoots lasers at a house? magic. a guy disappears into a parallel plane, body and all, for a day or so? absolutely magic. the moon exists as a living being on earth and brought a baby back to life? totally fucking magic. face stealing? magic as shit. your sister makes water levitate sometimes? how dare you sokka that's not magic it's martial arts.
Honestly I don't know where I was going for this except that it's fucking hilarious that this show has two separate and distinct systems of magic, but you're only allowed to call one of them magic because the other one happens too often.