The 12th man or 12th player is a collective term for fans of sports teams in many eleven-a-side games, in particular association football or American football. As most football leagues allow a maximum of eleven players per team on the playing field at a time, referring to a team's fans as the 12th man implies that they have a potentially helpful and significant role in the game.
The presence of fans can have a notable impact on how the teams perform, an element in the home advantage. Namely, the home team fans would vocally support and urge on their team to win the game. Thus these fans will often create loud sounds or chant in the hope of encouraging their team; or of distracting, demoralizing or confusing the opposing team while they have possession of the ball; or to persuade a referee to make a favorable decision to the team. Noises are made by shouting, singing, whistling, stomping, clapping and various other techniques.
In Canadian football, 12 players from each team are usually on the field at one time and the term 13th man is often used to refer to fans. Similarly, in Australian rules football 18 players are on the field and the fans are often referred to as the 19th man. However, in basketball, where five players are on the court, the term Sixth man generally refers to an energetic substitute player. Similarly, in rugby sevens, with seven players from each team on the field, "Eighth man" is not used to refer to fans as the term refers to the eighth forward in rugby union. The term Twelfth Man has a specifically different meaning in cricket, referring instead to the nominated first substitute player who fields when a member of the fielding side is injured during play.