line of scrimmage
- (American football) Either of two imaginary lines across the football field touching one of the two apices of the football which point toward either the defensive side or the offensive side before the center is allowed to touch the ball before each play.
The term line of scrimmage is used for both the line on the offensive side (offensive line of scrimmage) and the one on the defensive side (defensive line of scrimmage). The zone in between the two lines of scrimmage is called neutral zone. The defensive line of scrimmage is used by the head linesman and his assistants to measure advancements (gains or losses) of the football along the football field.