Offside, often pluralized as Offsides in American English, is a rule used by several different team sports regulating aspects of player positioning. It is particularly used in field sports with rules deriving from the various codes of football, such as association football, rugby union and rugby league, and in some other sports e.g. ice hockey, field hockey and bandy.
Offside rules are generally designed to ensure that players play together as a team, and do not consistently position one or a few players near the opponent's goal to try to receive a "Hail Mary pass" for an easy goal without opposing players nearby. However, the application and enforcement of offside rules can be complicated, and can sometimes be confusing for new players as well as for spectators.
The word "offside" comes from a military term for a man trapped behind enemy lines, where he is said to be "off the strength of his side". Offside rules date back to codes of football developed at English public schools in the early nineteenth century. These offside rules were often much stricter than in modern games. In some of them, a player was "off his side" if he was standing in front of the ball. This was similar to the current offside law in rugby, which penalizes any player between the ball and the opponent's goal. By contrast, the original Sheffield Rules had no offside rule, and players known as "kick throughs" were positioned permanently near the opponents' goal.
Offside in different sports
- Offside (American and Canadian football)
- Offside (association football)
- Offside (bandy)
- Offside (field hockey)—Historically a part of the sport, but officially abolished in 1998
- Offside (Golf Croquet)
- Offside (ice hockey)
- Offside (rugby)
Notable sports without an offside rule
- Australian rules football
- Gaelic football
- Many versions of association football with fewer than 11 players a side, including futsal, beach soccer, five-a-side football, and indoor soccer
- Basketball—with just five players, a team with one player significantly ahead of the opposing team can be easily scored against by the other team. However, there is a three seconds rule ("3 in the key") which helps prevent players from lingering near the opposing basket.
- Net sports such as volleyball and tennis—the net acts as a barrier between the opposing teams or players. However, volleyball does have rules about which players can "spike" the ball (hit it downward when it is above net height) and where.
- Squash and racquetball—opposing players are often very close to each other and a "let" may be called if a player interferes with an opposing player's ability to have a fair chance to hit the ball.