(idiomatic) An area intermediate between two mutually exclusive states or categories, where the border between the two is fuzzy.

(informal, US, military, aviation, research, espionage, ufology) A secret military facility, an airport, an airbase in Nevada Test and Training Range, Nevada, United States; A military base in Nevada, where advanced military aircraft are developed; foreign military aircraft are evaluated; and rumored to be where the US government hides extra-planetary alien visitors.

(air traffic control) an airspace within which it is dangerous for aircraft to fly.

An enclosed area, often outdoor, for the presentation of sporting events (sports arena) or other spectacular events; earthen area, often oval, specifically for rodeos (North America) or circular area for bullfights (especially Hispanic America).

The area measured from the outside surface of the outer building wall to the outside surface of the opposite outer building wall. Where balconies and mezzanine floors occur within the exterior walls of the building, they are included in this figure.

An international region in which obstacles to unrestricted trade have been reduced to a minimum.

A village in Saaremaa, Saare County, Estonia

(American spelling) Alternative form of grey area

(cricket) the central, rectangular area of the pitch onto which the bowlers may not run during their follow through

(Internet slang, humorous) Used to tout victory over an opponent, or simply as a humorous catchphrase.