Hockey is a type of sport in which players try to get points by hitting an object into the other team's goal with a stick. There are three main ways that hockey is played.

Field hockey is played with a ball on grass or astroturf. Teams have 11 players each. Field hockey is usually played outdoors, but there is indoor field hockey. Field hockey is played in the Summer Olympic Games.
Ice hockey is played on ice. Players on each team wear ice skates. They try to hit a small rubber disc called a hockey puck into the other team's goal. There are 6 players on each team. It can be played indoors or outdoors. Professionals play indoors in arenas. Ice hockey is one of the most popular sports in the world. It is played in the Winter Olympic Games.
Roller hockey is played on a roller hockey rink, usually inside. Players on each team wear roller skates. They try to hit a small plastic disk called a hockey puck into the other team's goal. There are 5 players on each team. There is no contact.