A touchdown (abbreviated as TD) is a scoring play in gridiron football. Scoring a touchdown grants the team that scored it 6 points. Whether running, passing, returning a kickoff or punt, or recovering a turnover, a team scores a touchdown by advancing the football into the opponent's end zone. More specifically, a touchdown is when a player is in possession of the ball, any part of the ball is in the end zone they are attacking, and the player is not down.
Because of the speed at which football happens, it is often hard for an official to make the correct call based on their vantage point alone. Most professional football leagues, such as the National Football League (NFL) and the Canadian Football League (CFL), as well as some college leagues, such as the National Collegiate Athletic Association (NCAA), allow certain types of plays to be reviewed. Among these plays are touchdowns, as well as all other scoring plays, dangerous or unsportsmanlike conduct by players or staff, out-of-bounds calls, the place on the field where the official spots the ball after a play, and turnovers. Coaches can also challenge calls, provided they are made during a play eligible to be reviewed; the only exception is during periods of the game where coaches' challenges are restricted, such as the last two minutes of each half. The NFL and CFL review all scoring plays and turnovers regardless of whether the call was questionable, and therefore do not allow coaches to challenge those plays, either. The NCAA allows Division I FBS teams to review plays throughout the regular season and postseason, while Division I FCS teams can only use it during the playoffs, Division II teams only during the quarterfinals, semifinals, and championship game, and Division III teams only during the semifinals and championship game.
