(historical) A former area between Saudi Arabia and Iraq, abolished 1991.

plural of dead zone

An area with no life. / (ecology) An area of the ocean where oxygen levels are too low to support life, especially as a result of pollution.

plural of abscission zone

(botany) The area in a plant's leaf, stem, or fruit stalk, where the abscission layer if formed along with weakened sclerenchyma, absent collenchyma, and dense cytoplasm.

(of a tidal coast) The intertidal zone / (of a non-flowing, non-tidal body of water) The zone of shallow water to the limit at which plants root.

(geography) The oceanic realm consisting of the deep ocean, typified by a dearth of plant life, and plentiful carnivorous animals that are able to withstand extreme pressure.

plural of orogenous zone

(geology, often humorous, by analogy to erogenous zone) A region characterized by mountain-building.

(UK) A street or group of streets designed primarily to meet the needs of pedestrians, cyclists, children and residents, and where motor traffic is limited.