Field officer

A field officer is an army, marine, or air force commissioned officer senior in rank to a company officer but junior to a general officer; in some navies, it is an officer who is a Lieutenant Commander, Commander, or Captain.

Historically, a regiment or battalion's field officers made up its command element.

United Kingdom and some Commonwealth countries
The British Army (in which these officers are called officers of field rank), and some others in the Commonwealth (including the Australian Army and New Zealand Army), also include the brigadier in this category: the equivalent in other armies is a general officer (the brigadier general).

United States
Today, a field officer in the United States (here called of field grade) Army, Marine Corps, and Air Force is typically a major, lieutenant colonel, or a colonel:"The [U.S.] commissioned officer corps is divided into 10 pay grades (O-1 through O-10). Officers in pay grades O-1 through O-3 are considered company grade officers. In the Army, Marine Corps, and Air Force, these pay grades correspond to the ranks of second lieutenant (O-1), first lieutenant (O-2), and captain (O-3), and in the Navy, ensign, lieutenant junior grade, and lieutenant. Officers in the next three pay grades (O-4 through O-6) are considered field grade officers. In the Army, Marine Corps, and Air Force, these pay grades correspond to the ranks of major (O-4), lieutenant colonel (O-5), and colonel (O-6), and in the Navy, lieutenant commander, commander, and captain. The highest four pay grades are reserved for general officers in the Army, Marine Corps, and Air Force, and flag officers in the Navy. The ranks associated with each pay grade are as follows: in the Army, Marine Corps, and Air Force, brigadier general (O-7), major general (O-8), lieutenant general (O-9), and general (O-10); in the Navy, rear admiral-lower half, rear admiral-upper half, vice admiral, and admiral."

Canada
In the Canadian Forces, the equivalent of field officers are senior officers (Officiers supérieurs); they include the army and air force ranks of Major, Lieutenant-Colonel, and Colonel, and the naval ranks of Lieutenant-Commander, Commander, and Captain.

France
In the French Forces, field officers are known as Commandant, Lieutenant-colonel and Colonel (Capitaine de corvette, Capitaine de frégate and Capitaine de vaisseau in the naval forces).

Germany
In the German forces, officers from Major to Colonel in the Army and Luftwaffe, or from Lieutenant Commander to Captain in the Navy are known as Stabsoffiziere (which could be translated as Staff Officers, though the meaning is different from that of "staff officer" in anglophone forces).