CONTROL AREA

place which is carefully regulated

A Control Area (CTA) is an aviation term that describes a volume of controlled airspace that exists in the vicinity of an airport. It has a specified lower level and a specified upper level. It usually is situated on top of a Control Zone and provides protection to aircraft climbing out from the airport.
See more at Wikipedia.org...

A controlled airspace extending upwards from a specified limit above the earth. (FAA4)

(As it pertains to the Interstate Highway System) A metropolitan area, city or industrial center, a topographic feature such as a major mountain pass, a favorable location for a major river crossing, a road hub which would result in material traffic increments on the Interstate route, a place on the boundary between two States agreed to by the States concerned, or other similar point of significance. (23CFR470)

A controlled airspace extending upwards from a specified limit above the earth. See also air control; airway; control zone; controlled airspace; terminal control area. 1/7/80

Espace aérien contrôlé situé au-dessus d'une limite déterminée par rapport à la surface. Voir aussi contrôle aérien; espace aérien contrôlé; voie aérienne; zone de contrôle; zone de contrôle terminale. 1/7/80

[ICAO]
A controlled airspace extending upwards from a specified limit above the earth.