Although people still argue about what is what, and some people feel that the name is not important, I thought you might like the definition, as given by 3run:
"Parkour: the art of forward movement. In parkour, every motion must be as close to 100% efficient as possible in taking you from point A to point B. Therefore vaults, drops, jumps, rolls, wall climbing, and catgrabs are part of parkour, but spins, flips, and direction reversals are usually not. "Traceurs" utilize obstacles and the spaces between them to create a forward flow, taking physical objects meant to restrict motion and using them to enhance it instead. A parkour video usually follows one or more traceurs in constant motion throughout an environment, as they overcome a variety of different challenges such as fences, walls, and gaps. Most parkour videos will include very few shots of "safe locations" such as a gym, because the key to parkour is interaction with the real, outside world, as in a chase, rescue, or emergency situation.
