Why do they call it cover 3?

Why do they call it cover 3? The three defensive backs help protect against long passes As the name implies, the cover 3 zone deploys three deep defensive backs to cover their respective thirds of the field (see figure). The basic philosophy behind the cover 3 zone is to provide a good balance of run and pass defense.

The three defensive backs help protect against long passes

As the name implies, the cover 3 zone deploys three deep defensive backs to cover their respective thirds of the field (see figure). The basic philosophy behind the cover 3 zone is to provide a good balance of run and pass defense.