| Acronym | Meaning |
| OPE | Operator Product Expansion |
| ROA | Relaxed Orbital Approximation |
| PWSB | Plane-wave Second Born |
| GCW | Groundwater Circulation Well |
| ABA | Acid-base Account [related To Acid-forming Potential] |
| DGT | Diffusive Gradients In Thin Films |
| SOS | Surfaces Of Section Method (semiclassical Calcn. Of Eigenvalues) |
| EXPRESSO | Experiment For Regional Sources And Sinks Of Oxidants |
| IVAP | Intimate Valence Alternation Pairs (bonding Model In Electronic Structure Calcns.) |
| LIOAS | Laser-induced Optoacoustic Spectroscopy |