Non-commissioned officer in the context of "Compagnie des Carabiniers du Prince"

A soldier is a person who is a member of an army. A soldier can be a conscripted or volunteer enlisted person, a non-commissioned officer, a warrant officer, or an officer.

Military personnel or military service members are members of the state's armed forces. Their roles, pay, and obligations differ according to their military branch (army, navy, marines, coast guard, air force, and space force), rank (officer, non-commissioned officer, or enlisted recruit), and their military task when deployed on operations and on exercise.

An officer is a person who holds a position of authority as a member of an armed force or uniformed service.

Broadly speaking, "officer" means a commissioned officer, a non-commissioned officer (NCO), or a warrant officer. However, absent contextual qualification, the term typically refers only to a force's commissioned officers, the more senior members who derive their authority from a commission from the head of state.

An enlisted rank (also known as an enlisted grade or enlisted rate) is, in some armed services, any rank below that of a commissioned officer. The term can be inclusive of non-commissioned officers or warrant officers, except in United States military usage where warrant officers/chief warrant officers are a separate officer category ranking above enlisted grades and below commissioned officer grades. In most cases, enlisted service personnel perform jobs specific to their own occupational specialty, as opposed to the more generalized command responsibilities of commissioned officers.

The term "enlistment" refers solely to a military commitment (whether officer or enlisted) whereas the terms "taken on strength" and "struck off strength" refer to a service member being carried on a given unit's roll.

Warrant officer (WO) is a rank or category of ranks in the armed forces of many countries. Depending on the country, service, or historical context, warrant officers are sometimes classified as the most junior of the commissioned officer ranks, the most senior of the non-commissioned officer (NCO) ranks, or in a separate category of their own. Warrant officer ranks are especially prominent in the militaries of Commonwealth nations and the United States.

The name of the rank originated in medieval England. It was first used during the 13th century, in the Royal Navy, where warrant officers achieved the designation by virtue of their accrued experience or seniority, and technically held the rank by a warrant, rather than by a formal commission (as in the case of a commissioned officer). Nevertheless, warrant officers in the British services have traditionally been considered and treated as distinct from non-commissioned officers.

A centurion (/sɛnˈtjʊəriən/; Latin: centurio [kɛn̪ˈt̪ʊrioː], pl. centuriones; Ancient Greek: κεντυρίων, romanized: kentyríōn, or Ancient Greek: ἑκατόνταρχος, romanized: hekatóntarkhos) was a professional non-commissioned officer in the Roman army who commanded a group of soldiers called a centuria or "century".

The term centurion is derived from the Latin word centurio, which itself originates from centum, meaning "hundred." Initially, centurions were commanders of a unit of roughly 100 soldiers, although the exact number varied over time and by period. The concept of the centurion emerged during the early Roman Republic (509–27 BCE), when Rome's military was based on citizen-soldiers organized into centuries (centuriae), units of 100 men within the Roman legion (legio).