field_of_battle has definitions from the fields of military,geography
[ noun ] (military,geography) a region where a battle is being (or has been) fought


"they made a tour of Civil War battlefields"

Used in print

(Dan McLachlan, Jr., "Communication Networks and...)

With troops dispersed on fields_of_battle rather than on the parade_ground , it may seem that a certain amount of monitoring is automatically enforced by the lines of communication .