puck

A hockey puck is either an open or closed disk used in a variety of sports and games. There are designs made for use on an ice surface, such as in ice hockey, and others for the different variants of floor hockey which includes the wheeled skate variant of inline hockey (a.k.a. roller hockey). They are all designed to serve the same function a ball does in ball games.
A closed disk hockey puck having the shape of a short cylinder made of vulcanized rubber is used in the sport of ice hockey. The closed disk has also been referred to as a "flat ball." Hockey pucks are designed for use on either an ice surface, dry floor, or underwater, though open disk designs have only been used on floors.Open disk hockey pucks have a hole, forming the shape of a toroid, for use in a particular style of floor hockey. They should not be confused with ringette rings, which are toruses, for use in the sport of ringette.
This article deals chiefly with the sport and game pucks which are closed disks.

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