When you run really fast, you sprint. You and your sister might sprint to the bus stop, racing to see who can get there first.
In the sport of track and field, a sprint is a short race that's run at top speed the whole way. Two professional cyclists also sprint when they race on bikes that start out side-by-side. If you notice a swarm of angry wasps heading your direction, you can sprint indoors, hoping you move faster than they do. Sprint has a Scandinavian root, possibly the Old Norse word spretta, "to jump up."