The United States Navy, like any organization, produces its own acronyms and abbreviations, which often come to have meaning beyond their bare expansions. United States Navy personnel sometimes colloquially refer to these as NAVSpeak. Like other organizational colloquialisms, their use often creates or reinforces a sense of esprit and closeness within the organization. Official acronyms For a comprehensive list of unit organizations in the United States Navy, see List of units of the United States Navy. # 1MC – 1 Main Circuit, shipboard public address system 2MC – 2 Main Circuit, same as 1MC, but limited to the engine room 3M – Maintenance and Material Management (3M System) 3MA – Maintenance and Material Management Assistant 3MC – Maintenance and Material Management Coordinator 3MI – Maintenance and Material Management Inspection 5MC – 5 Main Circuit, Carrier Flight Deck address system 27MC – Control Room to Sonar Room address system A A-STRIKE – Assistant STRIKE Operations Officer (Carrier Scheduler/Planner) AA – Airman Apprentice (E-2) AAW – Anti-Air Warfare AB – Aviation Boatswain's Mate ABE – Aviation Boatswain's Mate – Equipment (Launch and Recovery Systems) ABF – Aviation Boatswain's Mate (Fuels) ABFD – Advanced Base Floating Dry Dock, class/type of ship ABH – Aviation Boatswain's Mate (Aircraft Handling) AC – Air Traffic Controlman ACR – Armored cruiser, class/type of ship AD – Auxiliary, Destroyer Tender, class/type of ship AD – Aviation Machinist's Mate ADCON – Administrative control ADNS – Automated Digital Network System ADSW – Active Duty Special Work (U.S. Navy Reserve, type of active duty orders, typically 6 months in duration) ADT – Active Duty Training (U.S. Navy Reserve, type of active duty orders, typically more than 30 days but less than 6 months) AE – Auxiliary, Explosives, class/type of ship. An ammunition ship. AE – Aviation Electrician's Mate AF – Aviation Photographer's Mate AFC – Aviation Fire Control AFCM – Master Chief Aircraft Maintenanceman AFFF – Aqueous Film Forming Foam AFS – Auxiliary, Fast Stores, class/type of ship. A supply ship that carries a little bit of everything, nicknamed "7-11" AFSB – Afloat Forward Staging Base AG – Aerographer's Mate AIMD – Aircraft Intermediate Maintenance Department (or Detachment) AK – Auxiliary, Cargo, class/type of ship. An attack transport. AK – Aviation Storekeeper (outdated; merged into LS rating) ALNAV – All Navy ALPO – Assistant Lead Petty Officer AM – Aviation Structural Mechanic AME – Aviation Structural Mechanic – Environmental (Air Conditioning,