In sports, out of bounds refers to being outside the playing boundaries of the field. Due to the chaotic nature of play, it is normal in many sports for players and/or the ball to go out of bounds frequently during a game. The legality of going out of bounds, and the ease of prevention, vary by sport. In some cases, players may intentionally go or send the ball out of bounds when it is to their advantage.
Baseball
In baseball, there are two ways for a batted ball to be out-of-bounds. One is to exit the field of play between the foul lines. If this is achieved without touching the ground first, it is a home run, and the batter and teammates who are on base run to home plate and score a point for their team. If the ball bounced off the ground before exiting play, it is a ground rule double, and the batter and all runners not on third advance exactly two bases; runners only score if they were on second or third base. If the ball is hit outside the foul lines, it is a foul ball, and is equivalent to a strike, unless the batter has two strikes. The foul ball bounds do not apply to fielders, who are allowed to try to catch a foul ball, which would put the batter out. While the rules of baseball define the angle of the foul lines, there are no set rules as to how large a field should be, and it varies from baseball field to baseball field. Whether fielders can attempt to catch balls in dugouts or the stands varies. In major league baseball, it is possible in baseball for a dugout to be a factor in play. MLB rule 6.05 states that a fielder may reach into a dugout to catch a fly ball as long as one or both feet is on or over the playing field, and does not have a foot on the ground in the dugout when making the catch. MLB universal ground rules state that the player may subsequently enter the dugout after making the catch if his momentum is carrying him that way, but if he falls in the dugout as a result, the catch is allowed but baserunners advance in accordance with Rule 7.04. A live ball entering a dugout becomes dead and the batter-runner and any baserunners advance in accordance with Rule 7.04. However, a live ball bouncing off a dugout railing, if present, is still in play. Due to the dugouts' location in foul territory, live balls entering dugouts usually only occur after an errant throw by the defensive team. Individual leagues at levels below MLB are free to set their own rules governing the dugouts as is appropriate for their league's ballparks and playing level. For example, the rule governing reaching into dugouts to catch fly balls would not apply in leagues where the dugouts are separated from the field by a chain-link fence that is taller than the players.
Basketball
When the ball goes out of bounds, it shall be thrown into the court and played by the first person touching it. In case of dispute, the referee shall throw it straight into the court. The thrower-in is allowed five seconds. If he holds it longer, it shall go to the opponent. If any side persists in delaying the game, the referee shall call a foul on that side.
Football
Australian rules
In Australian rules football, the ball is considered out of bounds when the whole of the ball is outside the plane of boundary line; or, if any part of the ball touches the behind post. Under most circumstances, play is restarted by means of a boundary throw-in after it has gone out of bounds: the boundary umpire throws the ball high in the air and backwards over his head to a neutral contest 15-20m in from the line. Under the following circumstances, a free kick awarded against the team who put the ball out of bounds:
If the ball goes out of bounds on the full from a kick
If the ball goes out of bounds from a kick-in without being touched by another player
Gridiron code
In gridiron football, a play is considered to be dead if a ball or the player carrying the ball goes out of bounds. A forward pass thrown to a player who has one or both feet on the ground out of bounds is considered an incomplete pass regardless of whether it was caught or not. In the NFL, the clock stops whenever a player carrying the ball steps out of bounds or fumbles the ball out of bounds. Within the last 2 minutes of the first half, the last 5 minutes of the game, or after a change of possession, the clock remains stopped until the next snap; at all other times, the clock restarts when the referee signals indicating that the ball has been placed for the next down. In arena football, the field is walled so that play can almost never go out of bounds. At all other times, the clock keeps ticking. In college football, the clock stops when the ballcarrier goes out of bounds. If there are more than two minutes left in either half, the clock resumes when the umpire marks the ball as ready for the next play. If there are less than two minutes left in the half, the clock resumes upon the next play. If the player with the ball goes out of bounds in his own end zone, in most cases, it is considered to be a safety in favor of the other team. A ball kicked out of bounds through the end zone is a touchback; in Canadian football, this situation usually is awarded a single point. A kickoff that goes out of bounds is a penalty. Up through 1986, this required the kicking team to rekick the ball from five yards behind the spot of the original kickoff, unless the penalty was declined by the receiving team. In 1987, the NFL instituted a new rule, where the ball would be awarded to the receiving team five yards ahead of the spot where it went out of bounds. In Canadian football, if a fumble goes out of bounds, the team of the last player to touch it gets possession.
In ice hockey, if the puck gets knocked out of play, a face-off shall be conducted at the nearest face-off dot to where the puck had gone out of play. However, if the puck is directly shot out of bounds over the glass deliberately by a player such as a goaltender or any defensive player within their own defensive zone, a delay of gameminor penalty shall be assessed on the offending player.
Golf
In golf, "Out of Bounds" is beyond the boundaries of the golf course or any part of the course so marked by the committee in charge of the competition or the golf course.
If a ball is out of bounds, the player must play a ball, under penalty of one stroke, as nearly as possible at the spot from which the original ball was last played.
A golf ball is out of bounds when all of it lies out of bounds. A player may stand out of bounds to play a ball lying within bounds.
Reference: Rules of Golf 2012-2015, Section II Definitions.
Skiing
In skiing, an out of bounds area is considered one that is outside of the area owned/serviced by a ski resort. Out of bounds areas can either be accessed by ducking under a rope or fence, or through marked gates. Usually, if one is caught 'cutting a rope', one will lose skiing privileges at the ski resort; depending on where one does so, they may also be arrested for trespassing. Out of bounds areas are not serviced by any type of lift, thus one must usually hike out of the area. Also, out of bounds areas are not serviced by a resorts ski patrol and are not checked for avalanche potential, thus one must be properly equipped for avalanche rescue and understand that a rescue may be incredibly costly.
