What is a Hat Trick in Hockey?
A Rare Accomplishment
The main priority in hockey is to score goals, because the team that scores the most goals wins the game. A goal is awarded when the puck goes into the opponent's goal, usually after being shot by a player on the scoring team. Relatively few goals are scored in most hockey games, with teams often finishing a game with two goals or less, which is why it is considered a significant feat when a single player scores three goals in one game.
Natural Hat Trick
It does not matter when the player scores the three goals, as long as they are scored in a single game. If they are scored in succession — with no other goals scored in between — the accomplishment is often referred to as a natural hat trick. The same term also has been used to describe the feat of scoring one goal in each of the three periods of a game or the achievement of scoring three goals in a single period.
Origin of the Term "Hat Trick"
The use of the term "hat trick" to describe an achievement in sports is thought to have started in 1858, after a cricket bowler named H.H. Stephenson was awarded a hat after taking three wickets in three balls — an extremely rare feat in the sport of cricket. Exactly when the term came to be used in hockey is not known, but its use in hockey had become popular by the mid-1900s. About that time, there are believed to have been several hat companies that would award hats to players who had scored three goals in one game. Since at least that time, it has been a tradition for hockey fans to throw hats onto the ice when a player has scored a hat trick.
Source: WiseGeek