Description: A generic entity representing variously 'regions' (ICAO and otherwise), 'areas', 'zones', 'sectors' (elementary and/or consolidated), etc., as used in and by air traffic services, including those of the FUA concept, special regulated and client defined airspaces and all sorts of 'limited' airspaces. It is also used to identify 'political' and/or 'geographical' two-dimensional areas representing countries, coastlines and so on. It should be noted that countries and the like could be regarded, without restriction of the generality, as three-dimensional areas with MSL as lower and UNL as upper levels. Also a defined three dimensional region of space relevant to air traffic.