Petty officer in the context of "Superior (hierarchy)"

A non-commissioned officer (NCO) is an enlisted leader, petty officer, or in some cases warrant officer, who does not hold a commission. Non-commissioned officers usually earn their position of authority by promotion through the enlisted ranks.

In contrast, commissioned officers usually enter directly from a military academy, officer training corps (OTC) or Reserve Officers' Training Corps (ROTC), or officer candidate school (OCS) or officer training school (OTS), after receiving a post-secondary degree.

A midshipman is an officer of the lowest rank in the Royal Navy, United States Navy, and many Commonwealth navies. Commonwealth countries which use the rank include Canada (Naval Cadet), Australia, Bangladesh, Namibia, New Zealand, South Africa, India, Pakistan, Singapore, Sri Lanka, and Kenya.

In the 17th century, a midshipman was a rating for an experienced seaman, and the word derives from the area aboard a ship, amidships, either where he worked on the ship, or where he was berthed. Beginning in the 18th century, a commissioned officer candidate was rated as a midshipman, and the seaman rating began to slowly die out. By the Napoleonic era (1793–1815), a midshipman was an apprentice officer who had at least nominally served at least three years as a volunteer, officer's servant or able seaman, and was roughly equivalent to a present-day petty officer in rank and responsibilities. After serving at least three years as a midshipman or master's mate, he was eligible to take the examination for lieutenant. Promotion to lieutenant was not automatic, and many midshipmen took positions as master's mates for an increase in pay and responsibility aboard ship. Midshipmen in the United States Navy were trained and served similarly to midshipmen in the Royal Navy, although unlike their counterparts in the Royal Navy, a midshipman was a warrant officer rank until 1912.

Ship commissioning is the act or ceremony of placing a ship in active service and may be regarded as a particular application of the general concepts and practices of project commissioning. The term is most commonly applied to placing a warship in active duty with its country's military forces. The ceremonies involved are often rooted in centuries-old naval tradition.

Ship naming and launching endow a ship hull with her identity, but many milestones remain before it is completed and considered ready to be designated a commissioned ship. The engineering plant, weapon and electronic systems, galley, and other equipment required to transform the new hull into an operating and habitable warship are installed and tested. The prospective commanding officer, ship's officers, the petty officers, and seamen who will form the crew report for training and familiarization with their new ship.

Quartermaster is a military term, the meaning of which depends on the country and service. In land armies, a quartermaster is an officer or enlisted soldier who supervises logistics and requisitions, manages stores or barracks, and distributes supplies and provisions. In many navies, a quartermaster is a seaman or petty officer with responsibility for navigation and operation of the helm of a ship.

The term appears to derive from the title of a German royal official, the Quartiermeister. This term meant "master of quarters" (where "quarters" refers to lodging or accommodation). Alternatively, it could have been derived from "master of the quarterdeck" where the helmsman and captain controlled the ship. The term's first use in English was as a naval term, which entered English in the 15th century via the equivalent French and Dutch naval titles quartier-maître and kwartier-meester, respectively. The term began to refer to army officers in English around 1600.

A chief petty officer (CPO) is a senior non-commissioned officer in many navies and coast guards, usually above petty officer.