A military or armed force is a professional organization formally authorized by a sovereign state to use lethal or deadly force and weapons to support the interests of the state. It typically consists of branches such as an Army, Navy, Air Force, and in certain countries the Marines and Coast Guard. The task of the military is usually defined as defence of the state, and its citizens, and the prosecution of war against another state. The military may also have additional sanctioned and non-sanctioned functions within a society, including, the promotion of a political agenda, protecting corporate economic interests, internal population control, construction, emergency services, social ceremonies, and guarding important areas. The military may also function as a discrete subculture within a larger civil society, through the development of separate infrastructures, which may include housing, schools, utilities, logistics, health and medical, law, food production, finance and banking.
In broad usage, the terms "armed forces" and "military" are often treated as synonymous, although in technical usage a distinction is sometimes made in which a country's armed forces may include both its military and other paramilitary forces. Armed force is the use of armed forces to achieve political objectives. There are various forms of irregular military forces, not belonging to a recognized state; though they share many attributes with regular military forces, they are less often referred to as simply "military".
The profession of soldiering as part of a military is older than recorded history itself. Some of the most enduring images of the classical antiquity portray the power and feats of its military leaders. The Battle of Kadesh in 1274 BC was one of the defining points of Pharaoh Ramses II's reign, and is celebrated in bas-relief on his monuments. A thousand years later, the first emperor of unified China, Qin Shi Huang, was so determined to impress the gods with his military might, he was buried with an army of terracotta soldiers. The Romans were dedicated to military matters, leaving to posterity many treatises and writings, as well as a large number of lavishly carved triumphal arches and victory columns.
The first recorded use of the word military in English, spelled militarie, was in 1585. It comes from the Latin militaris (from Latin miles, meaning "soldier") through French, but is of uncertain etymology, one suggestion being derived from *mil-it- – going in a body or mass. The word is now identified as denoting someone that is skilled in use of weapons, or engaged in military service, or in warfare.
As a noun, the military usually refers generally to a country's armed forces, or sometimes, more specifically, to the senior officers who command them. In general, it refers to the physicality of armed forces, their personnel, equipment, and the physical area which they occupy.
As an adjective, military originally referred only to soldiers and soldiering, but it soon broadened to apply to land forces in general, and anything to do with their profession. The names of both the Royal Military Academy (1741) and United States Military Academy (1802) reflect this. However, at about the time of the Napoleonic Wars, 'military' began to be used in reference to armed forces as a whole, and in the 21st century expressions like 'military service', 'military intelligence', and 'military history' encompass naval and air force aspects. As such, it now connotes any activity performed by armed force personnel.
Military history is often considered to be the history of all conflicts, not just the history of the state militaries. It differs somewhat from the history of war, with military history focusing on the people and institutions of war-making, while the history of war focuses on the evolution of war itself in the face of changing technology, governments, and geography.