Definition of dead zone:
(n) :
(telecommunications) A region where mobile phones do not operate because there is no base station or repeater nearby.
(n) :
An area with no life.
(n) :
(ecology) An area of the ocean where oxygen levels are too low to support life, especially as a result of pollution.
(n) :
(sports, gridiron football) 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.
(n) :
(video games) A region within the player's viewpoint that is less sensitive to small movements, aiding accurate firing of weapons etc.
(n) :
(military, historical) 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.