The Alien RPG and The Colonial Marines Ops Manual have a plethora of abbreviations. Here is a list of most of them and their meaning(s).
AFF- Allied Frontier Force
APE- All Purpose Environment
CANC- Chinese/Asian Nations Cooperative
CBRN- Chemical, Biological, Radiological, and Nuclear
CCAF- Candian Colonial Armed Forces
CMB- Colonial Marshal Bureau
CSC- Central Space Consortium
CSC PMCC- Central Space Consortium Private Military Contractors
CSCSS- Central Space Commercial Star Ship (ICSC designation)
EEV- Emergency Escape Vehicle
FBI- Federal Bureau of Investigation
FTL- Faster Than Light
HMS- Her Majesty's Spaceship (3WE designation)
HMCSS- Her Majesty's Commercial Star Ship (3WE designation)
IASF- Imperial Armed Space Forces (3WE designation)
ICC- Interstellar Commerce Commission
ICSC- Independent Core System Colonies
LACN- Latin American Colonial Navy
MAU- Marine Assault Unit (USCMC designation)
MMEI- Major Military Expansion Initiative
MSS- Ministry of Space Security (UPP organization)
NDD(s)- Nuerological Distortion Disorder(s)
ORDF- Outer Rim Defense Fleet
PSV- People's Space Vessel (UPP designation)
RMC- Royal Marine Commandos (3WE designation)
SOF- Space Operating Forces (UPP designation)
SS- Star Ship (Private Vessel designation)
SSV- Space Security Vessel (UPP designation)
STSV- Space Towing and Salvage Vessel (Private Vessel designation)
3WE- Three World Empire
UA- United Americas
UAAC- United Americas Allied Command
UACG- United American Colonial Guard
UAORD- United Americas Outer Rim Defense (becomes ORDF)
UAS- United Americas Spaceship (Starship)
UNIC- United Nations Interplanetary Corps
UNISC- United Nations Interstellar Settlement Corps (latest iteration of UNIC)
UPP- Union of Progressive Peoples
UPPA- Union of Progressive Peoples Army
USASF- United States Aerospace Force
USCCG- United States Colonial Coast Guard
USCMC- United States Colonial Marine Corps
USCSS- United States Commercial Star Ship
USS- United States Starship (or Spaceship- US Military designation)