| Acronym | Meaning |
| ORI | Octane Requirement Increase |
| CAREIRS | Conversion And Renewable Energy Inquiry And Referral Service |
| APSG | Antisymmetrized Product Of Strongly Orthogonal Geminals (variant Of Multiconfiguration Self-consistent Field Method) |
| AADO | Angular (momentum Conservation) Average Dipole Orientation Theory (in Io-mol. Reactions) |
| CISA | Continuum Intermediate-state Approxn. (for Scattering) |
| EDA | Electron Donor-acceptor |
| IPM | Independent Particle Model |
| AHP | Average Hole-potential (method For Electronic-structure Calcns. On Mols.) |
| HVEM | Herpesvirus Entry Mediator |
| PPP | Positron Polarization Potential |