The way I see it, hacking refers to the ingenuity of coming up with a clever, self-made solution to a problem. It doesnt have to be computer related. A hack might be constructing the perfect-sized coffee scoop for your kitchen by designing the right spoon to meet your needs. Or a hack might involve making something from improvised materials. The reason so much hacking happens on computers is that the resources are free, and infinitely malleable. If you were creating art you would need art supplies, but on a computer your words build amazing structures for free.
Coding on the other hand, is simply the act of breaking apart human thought and encoding it into a format that is machine readable. Just because you are coding does not mean you are hacking.