| Acronym | Meaning |
| PMP4 | (spin) Projected Moeller-Plesset Fourth-order (perturbation Theory) |
| HAT | Humid-air Turbine [cycle] |
| ACPCSA | Adiabatic Capture Partial Centrifugal Sudden Approximation |
| RMF | Rotating Morse Function (in Potential-surface Calcn.) |
| CMOD | Crack Mouth Opening Displacement |
| NTU | Number Of Transfer Units (in Packed Tower Aeration System) |
| ICBN | International Code Of Botanical Nomenclature |
| MIDI | Split Valence Plus Polarization Function (basis Set) |
| OSC | Oxygen Storage Capacity |
| AFFF | Aqueous Film-forming Foam |