Aberdeen Test Center 
Advanced Technology Center 
Air Training Command 
Air Traffic Controller 
Armored Troop Carrier 
Air Target Chart 
Air Transport Command 
Air Temperature Control 
Air Threat Conference 
Air Training Corps 
air transportable clinic 
Armament Training Camp 
Army Training Center 
Assurance Technology Corporation 
Acquisition Tracking Center 
Advanced Technology Components 
Advanced Testing Capability 
AEGIS Training Center 
Agent Transfer Chamber 
Aided Target Classification 
Air Target Charts 
Air Traffic Control's 
Air Training Center 
American Technology Corporation 
American Truck Corporation 
Amphibious Training Center 
Analog Traffic Channel 
Armored Troop Carriers 
Armoured Troop Carrier 
Army Tactical Center