| Acronym | Meaning |
| APA | Administrative Procedure Act |
| PAP | Pancreatitis-associated Protein |
| PEEM | Panel Of Experts On Environmental Management |
| PTD | Photothermal Deflection |
| ESE | Electron Spin Echo |
| GGC | Generalized Gradient-corrected (density-functional) |
| EDSTAC | Endocrine Disruptor Screening And Testing Advisory Committee |
| NPS | National Park Service (US) |
| TOF | Turnover Frequency |
| NRAO | National Radio Astronomy Observatory |