Offside

In less than two games the World Cup has already brought one thing to light. A lot of people don’t understand offside rules. I think it’s safe to dub it the single most misunderstood rule in all of sports, partly because it differs so much from sport to sport.

Football

A player is in an offside position if he/she is in his opponents’ half of the field and is nearer to his opponents’ goal line than both the ball and the next to last opponent. [source]

American Football

A player is on the wrong side of the line of scrimmage when the ball is snapped. This foul occurs simultaneously with the snap. [source]

Hockey

If a player on the attacking team enters the attacking zone before the puck itself enters the zone, either carried by a teammate or sent into the attacking zone by an attacking player. [source]

Rugby

A defending player is offside if he is less than 10m away from the play-the-ball when the ball is played. An attacking player is offside if he is in front of the ball. [source]

Field Hockey

There used to be an offside rule, but it was abolished in the 1990s. [source]

Cricket

This is not actually a rule of offense, but instead is used to describe the formation of players on the field. [source]

One rule, same name, so many definitions.