An area with no life.
An area of the ocean where oxygen levels are too low to support life, especially as a result of pollution.
A region where mobile phones do not operate because there is no base station or repeater nearby.
(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.
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.
A region within the player's viewpoint that is less sensitive to small movements, aiding accurate firing of weapons etc.