neutral zone

Short definition from Wiktionary

Noun

1. 1
   A zone between the defensive line of scrimmage and the offensive line of scrimmage.
2. 2
   A zone on the playing surface between the attacking zone and the defending zone as delineated by the two blue lines.
3. 3
   A non-competitive segment of a bicycle race during which competitors have to stay behind the lead vehicles.
4. 4
   That space in the oral cavity where the forces exerted by the musculature of the tongue are equal and balanced with the forces exerted by the buccinator muscle of the cheek laterally and the orbicularis oris muscle anteriorly.
5. 5
   In Characeae, that line or place where rotating streams of protoplasm flow beside each other in opposite directions, shown by the absence of chlorophyll granules.

Proper noun

1. 1
   A former area between Saudi Arabia and Iraq, abolished 1991.