Trap run

In American football, a trap play, or trap run, is a run consisting of a defender on the line of scrimmage (either a defensive tackle or defensive end) getting trap blocked by an offensive lineman or back from the opposite (other side of the center) side of the ball. One of the defensive linemen will remained un-blocked on a trap and either a backside guard/tackle/h-back will pull down the line of scrimmage and kick him out so that the ball carrier can run inside of that trap block.

Typically, flow will start out one way (right or left) and the back will receive the ball going away from flow where the trap is taking place.