A-GPS stands for Assisted Global Positioning System (used in mobile communications as a positioning system)
A-GNSS stands for Assisted Global Navigation Satellite System (also seen as AGNSS)
A-Gang stands for Auxiliary Division (US Navy)
A-G stands for Air-to-Ground
A-FSM stands for Adaptation Finite State Machine (algorithms)
A-File stands for Administrative File
A-FIST stands for Abrams Full Crew Interactive Skills Trainer
A-ENWG stands for Ada-Europe Numerics Working Group (est. 1984)
A-EMCA stands for Advanced-Emergency Medical Care Assistant
A-FIVE stands for Agriculture, Forestry and Fisheries Fund Corporation for Innovation, Value-Chain and Expansion Japan (investment firm)