I would define a sport as any game that you have to practice before you play and condition your body to be better at.
Would this include ballet? They practice and have to condition their body for it. Sports are hard to define. You can play as a team or an individual, use a ball/puck etc. or not. I think the main thing for me to consider it to be a sport is that there needs to be competition involved. Driving in a NASCAR race is a sport, driving my car fast down the interstate is not a sport.