Original: The goaltender (also known colloquially as the goalie, goaler, or netminder) in ice hockey is the player who defends his team's goal net by stopping shots of the puck from entering his team's net, thus preventing the opposing team from scoring.
Simplified: The goaltender (also known colloquially as goalie or netminder) in ice hockey is the player who defends his team's goal net by stopping shots of the puck from entering his team's net, thus stopping the other team from scoring.