A foul in bowling occurs when a part of the bowler's body crosses and touches beyond the foul line during the delivery of the ball. The foul line is the line that separates the bowler's approach area from the lane where the ball rolls toward the pins. If the bowler steps over this line while throwing the ball, it is considered a foul. The main consequences of a foul in bowling are:
- Any pins knocked down during that throw do not count.
- The score for that ball is recorded as zero.
- If it happens in the first ball of the 10th frame, knocking down all pins on the second ball can still be counted as a spare, and the player may get a third ball.
Bowling alleys often use sensors to detect fouls automatically, and in professional games, officials or judges monitor fouls to maintain fairness. The foul line rule ensures safety by keeping players off the slippery lane surface and maintains fair play by having all players start their throws from the same distance behind the line. In short, fouling in bowling means crossing the foul line during the throw, resulting in no points being awarded for that delivery regardless of pinfall.
