In American football

American football

American football is a sport played between two teams of eleven with the objective of scoring points by advancing the ball into the opposing team's end zone. Known in the United States simply as football, it may also be referred to informally as gridiron football. The ball can be advanced by...

, a turnover occurs when the team with the ball loses possession of the ball, which is then gained by the other team. The two events that are officially classified as "turnovers" are fumble

Fumble

A fumble in American and Canadian football occurs when a player, who has possession and control of the ball loses it before being downed or scoring. By rule, it is any act other than passing, kicking or successful handing that results in loss of player possession...

s (accidental physical loss of a live ball a player has possession of) or interceptions

Interception (football)

An interception, intercept or pick is a move in many forms of football, including Canadian and American football, as well as rugby league, rugby union, Australian rules football and Gaelic football, which involves a pass, either by foot or hand, being caught by an opposition player, who usually...

 (passes intended for a member of the passing team, but caught by a member of the opposing team).

The term "turnover" is also used to refer to a turnover on downs

Turnover on downs

In American football, a turnover on downs occurs when a team fails to convert a fourth down into a first down by gaining the required yardage.A team has four chances to gain ten yards or to score. Any ground gained during one down short of these ten yards is kept for the next chance...

, when a team attempts to gain a first down or touchdown

Touchdown

A touchdown is a means of scoring in American and Canadian football. Whether running, passing, returning a kickoff or punt, or recovering a turnover, a team scores a touchdown by advancing the ball into the opponent's end zone.-Description:...

 on a fourth down play (known as a fourth down conversion), but is unsuccessful. When this occurs, the opposing team automatically gains possession at the spot to which the ball was advanced at the end of the play, unless a penalty

Penalty (American football)

In American football and Canadian football, a penalty is a sanction called against a team for a violation of the rules, called a foul. Officials initially signal penalties by tossing a bright yellow or orange colored "penalty flag" onto the field toward or at the spot of a foul...

has occurred (every defensive penalty, if accepted, results either in an automatic first down or a replay of down). The team that has lost possession is not permitted any opportunity to advance the ball any further.

Moreover, although all three are classified as "turnovers," the NFL game statistics recording turnovers only include lost fumbles and intercepted passes; turnovers on downs are not included (e.g., a team whose only turnovers are turnovers on downs is credited with having "no turnovers").