Air Traffic Control 
Automatic Temperature Control 
Aberdeen Test Center 
Advanced Technology Center 
Air Training Command 
Automatic Transmission Control 
address translation control 
Air Traffic Controller 
Armored Troop Carrier 
Air Target Chart 
Air Traffic Controllers 
Air Transport Command 
around-the-clock 
ATLAS-COPCO 
Absolute Time Command 
Active Thermal Control 
Adaptive Transform Coding 
Address Translation Cache 
Address Translation Controller 
Adiabatic Toroidal Compressor 
Ancillary Terrestrial Component 
Any Two Cards 
Applied Technology Council 
ATE Computer 
Athletic Trainer Certified 
automatic tube compensation 
Ablative Thrust Control 
Academic Technology Center 
acute toxic class 
Advanced Technical Center