To be a Sport, at least 2 of the following 3 must be true:
1. Outcome is decided by athletes, not judges
2. The athlete must do the majority of the work (not a horse or a car)
3. You must be able to actively play defense
Examples
Soccer is a sport (1, 2, & 3)
Running is a sport (1 & 2, but not 3)
Gymnastics is not a sport (2, but not 1 or 3)
Change my mind.