A sack in football is when a defensive player tackles the quarterback behind the line of scrimmage while he tries to pass the football.

What is the defensive tackles job?

Like other offensive linemen, their job is to block: to physically keep defenders away from the offensive player who has the football. The term "tackle" is a vestige of an earlier era of football, in which the same players played both offense and defense. A tackle is the strong position on the offensive line.

What defensive tackle has the most sacks?

Bruce Smith has the most career sacks by a defensive lineman, with 200 sacks.