[{"Bold_text": "noun", "List Items": ["a missile, usually round and made of iron or steel, designed to be fired from a cannon .", "Tennis.a served ball travels with great speed and describes little or no arc in flight.", "anything that moves with great speed, as an express train."]}, {"Bold_text": "adjective", "List Items": ["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."]}]