Corps

Military organization
Typical units	Typical numbers	Typical commander
fireteam	3–4	corporal
squad/ section	8–12	sergeant
platoon	15–30	lieutenant
company	80–150	captain/major
battalion/ cohort	300–800	lieutenant colonel
regiment/ brigade	2,000–4,000	colonel/ brigadier general
division/ legion	10,000–15,000	major general
corps	20,000–40,000	lieutenant general
field army	80,000+	general
army group	2+ field armies	field marshal/ five-star general
region/ theater	4+ army groups	Six-star rank

Common military ranks in English
Navies	Armies	Air forces
Commissioned and Non-commissioned officers
Admiral of the fleet	Marshal or Field marshal	Marshal of the air force
Admiral	General	Air chief marshal
Vice admiral	Lieutenant general	Air marshal
Rear admiral	Major general	Air vice-marshal
Commodore	Brigadier or Brigadier general	Air commodore
Captain	Colonel	Group captain
Commander	Lieutenant colonel	Wing commander
Lieutenant commander	Major or Commandant	Squadron leader
Lieutenant	Captain	Flight lieutenant
Sub-lieutenant	Lieutenant or First lieutenant	Flying officer
Ensign	Second lieutenant	Pilot officer
Midshipman	Officer cadet	Flight cadet
Enlisted grades
Warrant officer or Chief petty officer	Warrant officer or Sergeant major	Warrant officer
Petty officer	Sergeant	Sergeant
Leading seaman	Corporal	Corporal
Seaman	Private	Aircraftman

A corps (/ˈkɔər/; plural corps /ˈkɔərz/; via French, from the Latin corpus "body") is a military unit usually consisting of several divisions.

Some military service branches are also called corps, such as the Military Police Corps, Royal Logistic Corps, Quartermaster Corps, or Medical Corps.

A few civilian organizations use the name corps to imply a similar service level, such as the Peace Corps.

In many armies, a corps is a battlefield formation composed of two or more divisions, and typically commanded by a lieutenant general. During World War I and World War II, due to the large scale of combat, multiple corps were combined into armies which then formed into army groups. In Western armies with numbered corps, the number is often indicated in Roman numerals (e.g., VII Corps).

In the later stages of World War I, the five infantry divisions of the First Australian Imperial Force (AIF)—consisting entirely of personnel who had volunteered for service overseas—were united as the Australian Corps, on the Western Front, under Lieutenant General Sir John Monash.

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Wikipedia