Real Dictionary

cannonball
countable noun: A cannonball is a heavy metal ball that is fired from a cannon.

cannonball in American English
a heavy ball, esp. of iron, formerly used as a projectile in cannons
fast; rapid
to move very fast
adjective: made from a curled-up position with the arms pressing the knees against one's chest
noun: a missile, usually round and made of iron or steel, designed to be fired from a cannon

cannonball in British English
to rush along, like a cannonball
adjective: very fast or powerful
noun: a projectile fired from a cannon: usually a solid round metal shot