In tennis, a Cannonball serve is a powerful, flat serve hit with maximum speed and little spin.
It travels in a straight line, like a cannonball fired from a cannon. Players use this serve to overwhelm opponents with sheer velocity.
Cannonball serves are often difficult to return due to their speed. They were more common in earlier eras of tennis.
American player Maurice McLoughlin was nicknamed "The California Cannonball" for his fast serves in the 1910s. Today, players like John Isner and Ivo Karlovic are known for their powerful serves.