| Acronym | Meaning |
| HETE | High Energy Transient Explorer |
| IRRAS | Integrated Reliability And Risk Analysis System |
| ULTRA | Underground Leak Transport Assessment Model |
| MTCT | Mother-to-child Transmission |
| STEP | Solar Terrestrial Energy Program |
| EXFAS | Extended Fine Auger Structure |
| BIXE | Bombardment-induced X-ray Emission |
| MEV | Mink Enteritis Virus |
| NCI | National Cancer Institute |
| ENMR | Electrophoretic NMR |