noun - The breaststroke is a competitive swimming style in which the swimmer is on his or her chest and the torso does not rotate. It is also used in the game of water polo. the most popular recreational style due to its stability and the ability to keep the head out of the water a large portion of the time. The stroke itself is the slowest of any competitive strokes and thought to be the oldest of all swimming strokes. The other swimming styles include butterfly, backstroke, and freestyle.