| AA |
Antiaircraft |
| AAB |
Army Airforce Base |
| AACS |
Army Airways Communications System |
| AC |
Air Corps |
| ACF |
Air Corps Facility |
| AADA |
Advanced Air Depot Area |
| Admin |
Administration / Administrative |
| AES |
Marine Aviation Engineering Squadron |
| Afld |
Airfield |
| AM&S |
Administrative, Mess, and Supply |
| Arm |
Armored |
| Art |
Artillery |
| ARV |
Armored Recovery Vehicle |
| AS |
American Samoa |
| AT |
Antitank |
| ATG |
Antitank Gun |
| ATR |
Antitank Rifle |
| ATRL |
Antitank Rocket Launcher |
| Attd |
Attached |
| AUS |
Army of the United States |
| Aux |
Auxiliary |
| Avn |
Aviation |
| AW |
Automatic Weapons |
| BAD |
Base Air Detachment |
| BAR |
Browning Automatic Rifle (cal .30) |
| Bde |
Brigade |
| BDS |
Bomb Disposal Squad (Ordnance) |
| BLT |
Battalion Landing Team |
| Bn |
Battalion |
| Bty |
Battery |
| BWI |
British West Indies |
| CA |
Coastal Artillery |
| C&R |
Command and Reconnaissance |
| C&S |
Command and Staff |
| Cav |
Cavalry |
| Camo |
Camouflage |
| CCC |
Civilian Conservation Corps |
| CIC |
Counter Intelligence Corps |
| Co |
Company |
| CME |
Central Medical Establishment |
| Commo |
Communication(s) |
| COS |
Chief-of-Staff |
| Cp |
Camp |
| CZ |
Canal Zone |
| DD |
Duplex Drive. Amphibious tanks with flotation screens |
| Decon |
Decontamination |
| Det |
Detachment |
| Div |
Division |
| DUKW |
six-wheel-drive amphibious truck |
| EM |
Enlisted Man |
| Engr |
Engineer |
| (F) |
Fighter |
| FA |
Field Artillery |
| Fld |
Field |
| FO |
Forward Observer |
| Ft |
Fort |
| FTG |
Fighter Training Group |
| FTS |
Fighter Training Squadron |
| Gen Svc |
General Service |
| GHQ |
General Headquarters |
| Gp |
Group |
| (H) |
Heavy |
| H-D |
Horse Drawn |
| HD |
Harbor Defense |
| HHB |
Headquarters and Headquarters Battery |
| HHC |
Headquarters and Headquarters Company |
| HHD |
Headquarters and Headquarters Detachment |
| HHST |
Headquarters and Headquarters Service Troop |
| HHT |
Headquarters and Headquarters Troop |
| HMG |
Heavy Machine Gun |
| HMS |
Headquarters and Service Squadron – Marine Air Group |
| How |
Howitzer |
| Hqs / HQ |
Headquarters |
| HS |
Headquarters Squadron |
| HSC |
Headquarters and Service Company |
| HSS |
Headquarters and Service Squadorn – Base Air Detachment |
| Hy |
Heavy |
| (I) |
Interceptor |
| Inf |
Infantry |
| JASCO |
Joint Assault Signal Company |
| (L) |
Light |
| LG |
Landing Ground |
| LMG |
Light Machine Gun |
| (M) |
Medium |
| MAET |
Medical Air Evacuation Transport |
| Maint |
Maintenance |
| MAP |
Municipal Airport |
| MAM |
Medium Automotive Maintenance |
| MCAS |
Marine Corps Air Station |
| MCAF |
Marine Corps Air Facility |
| MCB |
Marine Corps Base |
| Met |
Meteorological (Weather) |
| MG |
Machine Gun |
| MI |
Mariana Islands |
| MI |
Military Intelligence |
| Mil |
Military |
| MP |
Military Police |
| MTU |
Mobile Training Unit |
| Mtz, Mot |
Motorized |