A field commander refers to a person who leads and controls military operations directly in the field or on the battlefield. They give orders to the soldiers, strategize, and make important decisions during combat. Full definition
It was not known until after the collapse of the Soviet Union that there were also tactical nuclear missiles deployed to Cuba and, for the only time, under direct authority of field commanders who could fire without further authority from Moscow, so if the US had decided to attack Cuba, as many urged JFK to do, there is a reasonable chance that local commanders would have begun a nuclear exchange. (dominiccummings.com)
If you're wondering what an enemy field commander is, it's pretty much the head honcho of the swarms of mechs attacking you; and when I say swarms, I'm referring to massive swarms, an ocean of mechs. (cogconnected.com)
Cyborg counter-cyberterrorist field commander The Major (played by Scarlett Johansson) commands a task force called Section 9 that fights cyber criminals and hackers. (orlandosentinel.com)