scrimmage: defense
The defense tries to prevent the opponent’s movement toward the end zone by stopping runs and passes.
neutral zone 
Gap the equivalent of one ball length, it separates the offense and defense on the line of scrimmage and cannot be crossed before the snap.
left cornerback 
Position at the far left of the main defensive line; this player is very fast and usually covers the opposing team’s wide receiver.
left safety 
Position behind the main defensive line on the left side of the field; an excellent tackler, this player is often relied on to stop running plays.
left defensive end 
Position on the outside of the left defensive tackle; this player pressures the quarterback and tries to stop the outside run.
middle linebacker 
Position behind the main defensive line; this player combines speed and size especially to stop running plays in the center of the field.
right safety 
Position behind the main defensive line on the right side of the field; this player is used mostly for the ability to cover passes.
outside linebacker 
Position near or behind the main defensive line on the right side of the field; agile and versatile, this player is effective against running and passing plays.
right cornerback 
Position at the far right of the main defensive line; this player is very fast and covers the opposing team’s wide receiver.
inside linebacker 
Position near or behind the main defensive line on the left side of the field; agile and versatile, this player is effective against passing and running plays.
left defensive tackle 
Position to the left of the middle linebacker; powerful and tough, this player is especially effective at stopping running plays.
right defensive tackle 
Position to the right of the middle linebacker; powerful and tough, this player is especially effective at stopping running plays.
right defensive end 
Position to the right of the right defensive tackle; this player pressures the quarterback and tries to stop outside runs.