| Acronym | Meaning |
| DEFCON | Defence Readiness Condition |
| PY | Paraguay (ISO 3166 Digram) - Person-Year -Portsmouth Yardstick |
| SU | Soviet Union (ISO 3166 Digram; Obsolete 1992) - Sudan (FIPS 10-4 Country Code) |
| GPMP | General Purpose Macro Processor |
| CAW | Canadian Auto Workers Trade Union |
| ARPA | Advanced Research Projects Agency |
| RBCI | Radio Based Combat Identification |
| RESNA | Rehabilitation Engineering And Assistive Technology Society Of North America |
| MDM | Michigan Dartmouth MIT Telescope Consortium |
| SADD | Students Against Drunk Driving (national School Related Group) |