A field officer or field grade officer is an army or marine commissioned officer senior in rank to a company officer but junior to a general officer. Army (From Latin armata (act of arming) via Old French armée) can, in some countries, refer to any armed force. ... A Marine is an elite warrior whose primary function is to serve aboard a ship and/or assault the land from the sea in amphibious warfare. ... In military organizations, a commissioned officer is a member of the service who derives authority directly from a sovereign power, and as such holds a commission from that power. ... In US military usage, a company officer is an US Army or US Marine commissioned officer below the rank of Major (abbreviated as MAJ): a Second Lieutenant (2LT), a (first) Lieutenant (1LT), or a Captain (CPT). ... General is a military rank, in most nations the highest rank, although some nations have the higher rank of Field Marshal. ...

Historically, a regiment or battalion's field officers made up its command element. A regiment is a military unit, consisting of a group of battalions, usually four and commanded by a colonel. ... Symbol of the Austrian 14th Armoured Battalion in NATO military graphic symbols A battalion is a military unit usually consisting of between two and six companies and typically commanded by a Lieutenant Colonel. ...

Today, a field officer is a major, lieutenant colonel, or a colonel. The British Army, 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). Major is a military rank the use of which varies according to country. ... In the U.S. Army, Air Force and Marine Corps, a lieutenant colonel is a commissioned officer superior to a major and inferior to a colonel. ... Colonel (IPA: or ) is a military rank of a commissioned officer, with the corresponding ranks existing in nearly every country in the world. ... The British Army is the land armed forces branch of the British Armed Forces. ... The English noun Commonwealth dates originally from the fifteenth century. ... The Australian Army is Australias military land force. ... Ngāti Tumatauenga or New Zealand Army is the land armed force of the New Zealand military and comprises around 4,500 regular personnel and 2,500 non-regulars and civilians. ... Brigadier is a rank which is used in different ways by different countries. ... A Brigadier General, or one-star general, is the lowest rank of general officer in the United States and some other countries, ranking just above Colonel and just below Major General. ...

In the Canadian Forces, the equivalent of field officers are senior officers (French: 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. The Canadian Forces (French: Forces Canadiennes), abbreviated as CF (French: FC) are the combined armed forces of Canada. ... In the Royal Navy, United States Navy, Royal Australian Navy, Royal New Zealand Navy, Canadian Forces Maritime Command (formerly the Royal Canadian Navy), United States Coast Guard, and many other navies and coast guards, a lieutenant commander (lieutenant-commander or Lt Cdr in the RN and abbreviated LCDR in the... Insignia of a United States Navy Commander Commander is a military rank used in many navies but not generally in armies or air forces. ... In the Canadian Forces, the rank of Captain (Navy) or Captain (N) (Capt(N)) (French: Capitaine de vaisseau or capv) is an Naval rank equal to a Colonel of the Army or Air Force. ...