American football is a team sport played by two teams of eleven players on a rectangular field with goalposts at each end. The offence, which is the team controlling the oval-shaped football, attempts to advance down the field by running with or passing the ball, while the defence, which is the team without control of the ball, aims to stop the offence's advance and aims to take control of the ball for themselves.
The offence must advance at least ten yards in three downs (CFL rules) or four downs (NFL rules), or plays, and otherwise they turn over the football to the defence; if the offence succeeds in advancing ten yards or more, they are given a new set of four downs. Points are primarily scored by advancing the ball into the opposing team's end zone for a touchdown or kicking the ball through the opponent's goalposts for a field goal. The team with the most points at the end of a game wins.