dead zone

noun

1. 1.An area with no life.
2. 2.An area of the ocean where oxygen levels are too low to support life, especially as a result of pollution.
3. 3.A region where mobile phones do not operate because there is no base station or repeater nearby.
4. 4.(gridiron football) Part of the field, entered by a player when they are on their opponent's side of the field but kicking a field goal would probably be unsuccessful and punting the ball would not dramatically change field position.
5. 5.Part of a fortification that is relatively sheltered from defending fire, because direct fire from other parts of the walls cannot be directed around a curved wall.