Words don't mean the same thing to everyone. And there is no real authority. Websters dictionary company or whatever is sometimes seen as one, but they are just a company trying to sell a product. So I don't think there is a rule on this. Since organized religion is a phrase used in various places, it implies the existance of unorganized religion. This would probably be a group of people who all believe the same thing, but there is no leadership and such. That would be tough to fit under spirituality. But neither interpretation is really wrong.