| Acronym | Meaning |
| VMO | Virtual Molecular Orbital |
| DI | Direct Injection (engine; Diesel) |
| REMPI | Resonance-Enhanced Multiphoton Ionization (for Mass Spectrometry) |
| IRAS | Infrared Reflection Absorption Spectroscopy |
| SUPERDARN | Super Dual Auroral Radar Network |
| ECWR | Electron Cyclotron Wave Resonance |
| PIMA | Polyisocyanurate Insulation Manufacturers Association |
| CCS | Cold Cranking Simulator |
| IHSS | International Humic Substances Society |
| BLMO | Best Limited Basis Molecular Orbital |