A zone blitz in football is a type of defensive pass rush in which multiple defenders rush the quarterback to make an effort to sack them, while some defensive players stay back in zone coverage to defend against the pass play. The primary element of the zone blitz is using defensive players that normally don't blitz to attack the quarterback, while defenders who are known for blitzing the quarterback stay back in zone coverage. The primary goal of a zone blitz is to reach the quarterback for a sack, but the zone coverage acts as a safety net if a pass is thrown.
The zone blitz is most often used when a defense wants to apply pressure to the quarterback, but still maintain some form of pass coverage in case they're not quick enough to get a sack. The zone blitz also allows for some trickery, as defensive linemen may drop back into coverage while defensive backs may blitz the quarterback. If used correctly, the defense may have an easy opening to the quarterback due to a fooled offensive linemen or missed assignment.