Glossary

Boot Camp - Colloquial name for Basic Training.
Cadet - An officer-in-training at the Academy, and attending the Officer Candidate School.
Chief - The common address for a Chief Petty Officer, sometimes for Senior Chief Petty Officer and occasionally for Master Chief Petty Officer.
Chief of the Boat (COB) - The designated title, regardless of rating, bestowed by the Commanding Officer upon the seniormost Chief, Senior Chief, or Master Chief of a vessel. On a base, this person is called a Command Chief.
Class - A distinction between rates of the same basic type but of different levels (also called "grade").
Clerical Officer - An administrative officer within a department of the Petty Officer rates who oversees Clerks.
Clerk - An administrative assistant within a department of the rates of Crewman Apprentice or Crewman who is overseen by a Clerical Officer.
Command Chief (CC) - see Chief of the Boat.
Commanding Officer (CO) - A commissioned officer who has authority and responsibility for a ship or starbase. COs are usually Commanders, Captains, and above.
Commission - A grant by the Federation Council to a new officer that gives him/her the authority of office.
Crewman - The highest of three of the lowest noncommissioned rates. The common address for those three rates (usually capitalized). Also sometimes used for enlisted personnel of a ship or base in total (usually lowercase).
Department Head - A Chief Warrant or commissioned officer in charge of a division of the ship's or base's facilities.
Enlisted - Another name for a crewman or noncommissioned officer.
Executive Officer (XO) - A commissioned officer who is the assistant to the Commanding Officer and next in the chain of command. XOs are usually Lieutenant Commanders and Commanders.
Flag Officer - A commissioned officer of the rank of Commodore or above.
Junior Officer - An officer who is not a department head or member of the Senior Staff.
Master Chief - The common address for a Master Chief Petty Officer.
Mate - A general title for the top-ranking noncomm in a given department, including Quartermasters and Yeomen.
Noncommissioned Officer (NCO or noncomm) - An enlisted member of the crew who serves without a commission. Can be used to mean all enlisted personnel or just Petty Officers and Chief Petty Officers.
Non-Playing Character (NPC) - A role that is not filled by a player, unless temporarily. NPCs, once created, are generally "public domain" ("shareware") and may be used by all players unless specific instructions are established through the chain of command regarding authority over the role.
Officer - A member of the crew holding a commission.
Officer Candidate School (OCS) - The training facility at the Academy for potential officers.
Petty Officer - Any one of three noncommissioned rates between Crewman and Chief.
Rank - A level of authority (and pay grade) for an officer (commissioned or Warrant) in Starfleet.
Rate - A level of authority (and pay grade) for a noncommissioned officer in Starfleet.
Rating - The position held by a noncommissioned officer in Starfleet.
Recruit - A crewman-in-training at the Academy, and attending the Recruit Basic Training.
Recruit Basic Training (RBT) - Also "Basic Training". The training facility at the Academy for potential crewmen.
Section - A division within a department of generally-similar duties. Senior Chief - The common address for a Senior Chief Petty Officer.
Senior Officer - An officer who is a department head or member of the senior staff (including the Executive Officer.)
Specialist - An NPC Petty Officer of any class who usually oversees a section.
Technician - An NPC Crewman or Crewman Apprentice whose duties generally include the maintenance of a departmental section.
Warrant - A grant by the Federation Council to a noncommissioned officer that gives him/her a limited form of commission.
Yeoman - An administrative and personal assistant to the Commanding Officer of the Petty Officer ranks.