Sergeant major
A sergeant major is a senior non-commissioned officer or warrant officer, depending on the country and military service in question.
In the U.S. Army, Sergeant Major refers to both a military rank and to a specific administrative position. The rank refers to the highest enlisted rank, just above Master Sergeant, with a pay grade of E-9.
The administrative position, Command Sergeant Major, is the senior enlisted advisor to the commanding officer and carries with it certain ceremonial functions such as caring for the units colors. Additionaly, they serve as monitors for and advocates of the enlisted men in the command.
An alternate usage of Command Sergeant Major is the senior NCO of a headquarters unit at battalion level or above; the soldier filling this position should carry the rank of Sergeant Major, but personnel shortages may, from time to time, force this sergeant major position to be held by a senior Master Sergeant.
There exists one post, Sergeant Major of the Army, which is unique. The holder of this post represents the most senior enlisted member in the U.S. Army. The current incumbent is SMA Kenneth O. Preston.
In the U.S. Marine Corps, Sergeant Major refers to a specific administrative position for a Master Gunnery Sergeant.
In the military of the United Kingdom sergeant major refers to the senior warrant officer in a company or battalion. There is no UK rank with this name. See Regimental Sergeant Major