noun Also cannon ball.
- a missile, usually round and made of iron or steel, designed to be fired from a cannon.
- Tennis. a served ball that travels with great speed and describes little or no arc in flight.
- anything that moves with great speed, as an express train.
- made from a curled-up position with the arms pressing the knees against one’s chest: a cannonball dive.
- moving at great speed: a train known as a cannonball express.
- a projectile fired from a cannon: usually a solid round metal shot
- a very fast low serve
- (as modifier)a cannonball serve
- a jump into water by a person who has his arms tucked into the body to form a ball
- (often foll by along, etc) to rush along, like a cannonball
- to execute a cannonball jump
- very fast or powerful