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