Does religion need a definition? is it the practice that defines it or does the definition define the practice? It would be like defining the word sport. There are different kinds of sports practiced in different ways, meaning they all have different definitions even ones that are debated on, such as ballet or MMA. It doesn't make the sport any less real. The definition of sport is an activity involving physical exertion and skill in which an individual or team competes against another or others for entertainment. Many sports fall under that category and many don't, yet we still consider them sports whether or not we get excitement out of them. The definition is not what matters but what physically is being presented. It is not the actual belief but more of the similar physical practice.