Sergeant

Sergeant (normally abbreviated to Sgt) is a rank used in some form by most militaries, police forces, and other uniformed organizations around the world. Its origins are the Latin serviens, "one who serves", through the French term sergent.

In most armies the rank of sergeant is classified by NATO as OR-5 and corresponds to command of a squad (or section). In Commonwealth armies, it is a more senior rank OR-6, corresponding roughly to a platoon second-in-command. In the United States Army, sergeant is a more junior rank corresponding to a four-man fireteam leader (OR-4), while still equivalent to OR-5.

More senior non-commissioned ranks are often variations on sergeant, for instance staff sergeant, regimental sergeant major, sergeant first class, master sergeant, first sergeant and sergeant major. The spelling "serjeant" is used in a few regiments of the British Army.

Army
In the United States Army, although there are several ranks of sergeant, the lowest carries the title of sergeant (SGT). Sergeant is the enlisted rank in the U.S. Army above specialist and corporal and below staff sergeant, and is the second-lowest grade of non-commissioned officer. The rank was often nicknamed "buck sergeant" to distinguish it from other senior grades of sergeants. Sergeants in the infantry, for example, lead fire teams of four men. There are two fire teams in a 9-man rifle squad, which is led by a staff sergeant. In the United States Army, sergeants, staff sergeants, sergeants first class, and master sergeants are typically referred to in short form by their subordinates as "sergeant", except in some training environments, or "first sergeant" in the case of first sergeants and "sergeant major" in the case of sergeants major, command sergeants major and the Sergeant Major of the Army. However, it is considered a good manner to address junior E-8 by their full rank, time allowing, or always when they request it.[citation needed] Drill sergeants are typically addressed as "drill sergeant" regardless of rank, though this term is used depending on post policy. When serving a tour as drill sergeant this is indicated by the traditional campaign hat, commonly referred to as the "brown round" or "smokey bear". The drill sergeant will always wear the drill sergeant badge indicating he completed the school. The army drill sergeant badge appears on the right breast pocket.

Marine Corps
The United States Marine Corps has several ranks that carry the title of sergeant, the lowest of which is sergeant (E-5). Marine sergeants are the fifth enlisted rank in the U.S. Marine Corps, just above corporal and below staff sergeant. Once a Marine reaches sergeant, their promotion no longer derives from a composite or cutting score; instead, they receive a fitness report (i.e., a formal written evaluation, grading attributes from appearance and bearing to leadership and technical proficiency). Sergeants serve as squad leaders or platoon guide in an infantry platoon, while staff sergeants serve in the billet of "platoon sergeant" in rifle platoons and "section leader" in weapons platoons (i.e., machine guns, mortars, anti-tank/assault weapons) An experienced gunnery sergeant in the infantry is typically in charge of coordinating operations and individual training for a company-sized group of Marines (approximately 180 personnel). Infantry gunnery sergeants usually serve as platoon sergeant for a heavy weapons platoon before moving up to the Company Gunnery Sergeant billet. The US Marine sergeant is often referred to as the backbone of the Marine Corps. In the Marine Corps, enlisted ranks above sergeant are referred to as staff non-commissioned officers, or SNCOs. These ranks, staff sergeant through sergeant major, are always referred to by their full rank and never merely as "sergeant". Gunnery sergeants are commonly addressed as simply "Gunny" informally. Master sergeants are addressed as "Master Sergeant" or "Top" at the preference of the marine wearing the rank and dependent on the MOS community. Master gunnery sergeants follow the same protocol but are commonly referred to as "Master Guns", or "Master Gunny".