Wiktionary
n. (context military English) Rear part of a theater of war or theater of operations (behind but contiguous to the combat zone) which contains the lines of communications, establishments for supply and evacuation, and other agencies required for the immediate support and maintenance of the field forces. Also called '''COMMZ'''.
Wikipedia
Communications Zone is a US Army and NATO term which describes a part of the theater of war operations.
The Communications Zone is the rear part of theater of operations (behind but contiguous to the combat zone) which contains the lines of communications, establishments for supply and evacuation, and other agencies required for the immediate support and maintenance of the field forces.