ATC assigned airspace

ATC assigned airspace

Airspace, of defined vertical or lateral limits, assigned by ATC (air traffic control) to provide air traffic segregation between specified activities being conducted within the assigned airspace and other IFR (instrument flight rules) traffic.
An Illustrated Dictionary of Aviation Copyright © 2005 by The McGraw-Hill Companies, Inc. All rights reserved
References in periodicals archive ?
You'll also find ATCAA in the Pilot-Controller glossary, where it spells out the meaning of the acronym: "ATC ASSIGNED AIRSPACE: Airspace of defined vertical/lateral limits, assigned by ATC, for the purpose of providing air traffic segregation between the specified activities being conducted within the assigned airspace and other IFR air traffic."