English abbreviations from a to aa
- a (Atto-)
- A&A ((publication) Astronomy & Astrophysics, a European scientific journal)
- A/C (aircraft commander)
- a/c. (Account)
- A/Cdre (Air Commodore)
- A/CNK (Al2O3/( CaO + Na2O + K2O) ( Shands Index))
- A/D (Analog/Digital)
- A&D (Admission and Disposition (report))
- A/DACG (Arrival/Departure Airfield Control Group)
- A/DCG (Arrival/Departure Control Group)
- A&DSL (Administrative and Direct Support Logistics)
- A&E (Arts & Entertainment Network, the original name for the U.S. TV channel now known as A&E Network)
- A/E (Aircraft Engineering)
- A/ETF (Automated/Electronic Target Folder)
- A/L (Administrative/Logistics)
- A/M (Approach and Moor)
- A&M (Agricultural & Mining)
- A/MLCMC (Aviation/ Missile Life Cycle Management Command)
- A/N (AlphaNumeric)
- A/NM (Administrative/Network Management)
- A/P (Autopilot)
- A&P (Administrative and Personnel)
- A&Q (Alert and Que)
- A/S (Anti-submarine)
- A&S (Armament & Standardisation)
- A/SP/A (Also Spelled As ....)
- A/T (autothrottle)
- A&T (North Carolina Agricultural & Technical State University)
- A/V (Arteriole–venue ratio)
- A0 (FAAD C2I Workstation computer unit)
- A10 (Atlantic 10 Conference)
- A1C (Airman First Class (from 1952 to 1967 it was A2C))
- A1F (Alpha-One Foundation)
- A2 (Antenne 2 ( France))
- A-2 (Intelligence Staff section of United States Army Air Corps)
- A2ATD (Anti-Armor Advanced Technology Demonstrator)
- A2ATD or A2ATD (Anti-Armour Advanced Technology Demonstration)
- A2C (Airman Second Class (from 1952 to 1967 – now A1C))
- A2C2 (Army Airborne Command and Control)
- A2C2 or A2C2 (Army Airspace Command and Control)
- A2C2S (Army Airborne Command and Control System)
- A2I2K (Army Airborne Intelligence 2000)
- A2S3 (AFATDS Application Software Segment Specification)
- A-3 (Air Force Operations Directorate)
- A3 (Armor/ Anti-Armor)
- A3C (Airman Third Class (from 1952 to 1967 – now Amn))
- A3MP (Armor/ Anti-Armor Master Plan)
- A4 (many, including a European standard office paper size; see entry)
- A-4 (Air Force Logistics Directorate)
- A4L (Abilities For Life)
- A-5 (Air Force Plans Directorate)
- A99ID (Associates of the 99th Infantry Division)
- AA (anti-aircraft)
- A.A. (Augustiniani Assumptionis (Assumptionists))