dead zone

Short definition from Wiktionary

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
   The part of the field where a player is 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
   An area near 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.
6. 6
   A region within the player's viewpoint that is less sensitive to small movements, aiding accurate firing of weapons etc.