Wiktionary
zone of fire
n. (context military English) An area into which a designated ground unit or fire support ship delivers, or is prepared to deliver, fire support. fire may or may not be observed.
Usage examples of "zone of fire".
The unholy slurry slowed their movement through that beaten zone and increased their time in the zone of fire.
Twenty-five of the other troopers were stationed in between, so there was almost a contin- uous zone of fire.