Association football, commonly known as football or soccer, is a team sport played between two teams of 11 players each. It is widely considered to be the most popular sport in the world. A ball game, it is played on a rectangular grass field, or occasionally on artificial turf, with a goal at each end of the field. The object of the game is to score by manoeuvring the ball into the opposing goal; only the goalkeepers may use their hands or arms to propel the ball in general play. The team that scores the most goals by the end of the match wins. If the score is tied at the end of the game, either a draw is declared or the game goes into extra time and/or a penalty shootout, depending on the format of the competition.
The modern game was codified in England following the formation of the Football Association, whose 1863 Laws of the Game created the foundations for the way the sport is played today. Football is governed internationally by the Federation Internationale de Football Association (International Federation of Association Football), which is commonly known by the acronym FIFA. The most prestigious international football competition is the World Cup, held every four years. This event, the most widely viewed and famous in the world, boasts twice the audience of the Summer Olympics.
Football is played in accordance with a set of rules, known as the Laws of the Game. The game is played using a single round ball (the football) and two teams of eleven players each compete to get the ball into the other team's goal, thereby scoring a goal. The team that has scored more goals at the end of the game is the winner; if both teams have scored an equal number of goals, then the game is a draw. There are exceptions to this rule, however; see Duration and tie-breaking methods below.
The primary rule is that the players (other than the goalkeepers) may not intentionally touch the ball with their hands or arms during play (though they do use their hands during a throw-in restart). Although players usually use their feet to move the ball around, they may use any part of their bodies other than their hands or arms.
In typical game play, players attempt to propel the ball toward their opponents' goal through individual control of the ball, such as by dribbling, passing the ball to a team-mate, and by taking shots at the goal, which is guarded by the opposing goalkeeper. Opposing players may try to regain control of the ball by intercepting a pass or through tackling the opponent who controls the ball; however, physical contact between opponents is limited. Football is generally a free-flowing game, with play stopping only when the ball has left the field of play, or when play is stopped by the referee. After a stoppage, play recommences with a specified restart.
At a professional level, most matches produce only a few goals. For example, during the English 2005-06 season of the FA Premier League, an average of 2.48 goals per match were scored.
The Laws of the Game do not specify any player positions other than goalkeeper, but a number of player specialisations have evolved. Broadly, these include three main categories: strikers, or forwards, whose main task is to score goals; defenders, who specialise in preventing their opponents from scoring; and midfielders, who dispossess the opposition and keep possession of the ball in order to pass it to the forwards; players in these positions are referred to as outfield players, in order to discern them from the single goalkeeper. These positions are further differentiated by which side of the field the player spends most time in. For example, there are central defenders, and left and right midfielders. The ten outfield players may be arranged in these positions in any combination (for example, there may be four defenders, four midfielders, and two forwards, or three defenders, three midfielders, and four forwards), and the number of players in each position determines the style of the team's play; more forwards and fewer defenders would create a more aggressive and offensive-minded game, while the reverse would create a slower, more defensive style of play. While players may spend most of the game in a specific position, there are few restrictions on player movement, and players can switch positions at any time. The layout of the players on the pitch is called the team's formation, and defining the team's formation and tactics is usually the prerogative of the team's manager.