| Acronym | Meaning |
| LCRA | Linear Combination Of Rydberg Orbitals |
| EDW | Exchange Distorted-wave |
| PERCI | Photoelectron Resonance Capture Ionization |
| UNOS | United Network For Organ Sharing |
| CCG | Continental Collision Granitoids |
| PIRANHA | Pesticide And Industrial Chemical Risk Analysis And Hazard Assessment |
| FTP | US Federal Test Procedure (for Exhaust Catalysts) |
| MWH | Mulliken-Wolfsberg-Helmholz (molecular Orbital Method) |
| FRCA | Fire Retardant Chemicals Association |
| ACO | Atomic-cell Orbital |