A "puck" is a small, hard disk used in the sport of ice hockey. It is typically made of rubber and is about three inches in diameter and one inch thick. The puck is essential for gameplay, as players use their sticks to pass, shoot, and score goals. In addition to ice hockey, pucks are also used in other sports, such as field hockey and roller hockey. The design of the puck allows it to slide smoothly on the ice, making it easier for players to control and maneuver during a game.