Captain (Australian Army)

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

The army rank of captain (from the French capitaine) is a commissioned officer rank historically corresponding to the command of a company of soldiers. The rank is also used by some air forces and marine forces. Today, a captain is typically either the commander or second-in-command of a company or artillery battery (or United States Army cavalry troop or Commonwealth squadron). In the Chinese People's Liberation Army, a captain may also command a company, or be the second-in-command of a battalion.

In NATO countries, the rank of captain is described by the code OF-2 and is one rank above an OF-1 (lieutenant or first lieutenant) and one below an OF-3 (major or commandant). The rank of captain is generally considered to be the highest rank a soldier can achieve while remaining in the field.

In some militaries, such as United States Army and Air Force and the British Army, captain is the entry-level rank for officer candidates possessing a professional degree, namely medical professionals (doctors, pharmacists, dentists) and lawyers. (In the United States Army, lawyers who are not already officers at captain rank or above enter as lieutenants during training, and are promoted to the rank of captain after completion of their training if they are in the active component, or after a certain amount of time, usually one year from their date of commission as a lieutenant, for the reserve components.)

...
Wikipedia