Major General

A Major General ranks immediately below a Lieutenant General and above a Brigadier General in the US Army and Brigadier in the British Army.
In the US Army, Marine Corps and Airforce a Major General is a two-star General. For insignia in the British Army see General.
A Major General is equivalent to a Rear Admiral (upper half) in the US Navy and Rear Admiral in the Royal Navy. Its equivalent rank the the Royal Air Force and airforces of many Commonwealth countries is Air Vice Marshal
See also: wiktionary definition of and Comparative military ranks.