| Acronym | Meaning |
| RTU | Remote Terminal Unit |
| R2PI | Resonant Two-photon Ionization |
| ROBK2 | Relativistic Second-order Oppenheimer-Brinkman-Kramers (in Ion-scattering Calcns.) |
| PCEM | Point-charge Electrostatic Model |
| FEGO | Floating Ellipsoidal Gaussian Orbital |
| UEGO | Universal Exhaust Gas Oxygen Sensor |
| MCPSAG | Marcus-Coltrin-Path Semiclassical Adiabatic Ground-state (transmission Coeffs.) |
| PLC | Phospholipase C |
| ITS | Internal Transcribed Spacer |
| GRVB | Generalized Resonating Valence Bond |