A
| AA | Always Afloat |
| AAAA | Always Afloat, Always Accessible |
| AAOSA | Always Afloat Or Safe Aground |
| AAR | Against All Risks |
| AARA | Always Accessible or Reachable on Arrival |
| AB | Able Seaman |
| ABS | American Bureau of Shipping |
| AC | Alternating Current (electricity) |
| ACV | Air Cushion Vehicle |
| AD | Area Differential |
| ADF | Automatic Direction Finder |
| AF | Anti-Fouling |
| AFFF | Aqueous Film Forming Foam |
| AFRA | Average Freight Rate Assessment |
| AG | Arabian Gulf |
| AGW | Actual Gross Weight |
| All Going Well | |
| AHTS | Anchor Handling Tug and Supply Vessel |
| AIS | Automatic Identification System |
| ALERT | Automatic Life-saving Emergency Radio Transmitter |
| ALRS | Admiralty List of Radio Signals |
| AMSL | Above Mean Sea Level |
| AMVER | Automated Mutual Assistance Vessel Rescue System |
| AMWELSH | Americanised Welsh Coal Charter party |
| ANERA | Asia-North America Eastbound Rate Agreement |
| ANOP | Articles Not Otherwise Provided for |
| ANSI | American National Standard Institute |
| AO | Awaiting Orders |
| And Other | |
| AOB | Any One Bottom |
| AOH | After Office Hours |
| AOLOC | Any One Location |
| AOR | Atlantic Ocean Region |
| AOS | Any One Steamer |
| AOV | Any One Vessel |
| AP | All Purposes |
| Additional Premium | |
| Aft Perpendicular | |
| API | American Petroleum Institute |
| APS | Arrival Pilot Station |
| APT | Aft Peak Tank |
| ARA | Antwerp – Rotterdam – Amsterdam |
| ARPA | Automatic Radar Plotting Aid |
| A/S | Alongside |
| ASAP | As Soon As Possible |
| ASBA | The Association of Shipbrokers and Agents (USA) Incorporated, New York |
| ASCII | American Standard Code for Information Interchange |
| ASPW | Any Safe Port in the World |
| ASTM | American Society of Testing & Materials |
| ATA | Actual Time of Arrival |
| ATD | Actual Time of Departure |
| ATDN | Any Time Day & Night |
| ATDNSHINC | Anytime Day/Night Sundays & Holidays Included |
| ATK | Aviation Turbine Kerosene |
| ATS | All Time Saved |
| ATSBE | All Time Saved Both Ends |
| ATSDO | All Time Saved Discharging Only |
| ATUTC | Actual Times Used To Count |
| AUV | Autonomous Underwater Vehicle |
| AVGAS | Aviation Gasoline |
| AVR | Automatic Voltage Regulator |
| AVTAG | Aviation Turbine Gasoline |
| AWIWL | Always Within Institute Warranty Limits |
| AWVNS | Always Within Vessel`s Natural Segregation |
| AWRI | Additional War Risk Insurance |
Source : International Maritime Acadamy
