| Acronym | Meaning |
| APD | Action Potential Duration |
| POS | Points-on-a-sphere (repulsion Potential Model |
| POTW | Publicly Owned Treatment Works |
| CPOM | Coarse Particulate Organic Matter |
| IBS | Incomplete Basis Set |
| BCGA | British Compressed Gases Association |
| IECT | Impulsive Ergodic Collision Theory |
| NRA | Neutron Reaction Analysis |
| ECDL | External-cavity Diode Laser |
| PO | Polarization Orbital |