| Acronym | Meaning |
| SRA | Sudden Rotation Approximation |
| RUSTIC | Risk Of Unsaturated/saturated Transport And Transformation Of Chemical Concentrations |
| ABR | Anaerobic Baffled Reactor (for Wastewater Treatment) |
| ACE | Angiotensin-converting Enzyme |
| PBB | Polybrominated Biphenyl |
| HRPA | Higher Random Phase Approximation |
| ARMAX | Autoregressive Moving Average Exogenous |
| ERP | Effective Refractory Period |
| BSO | Basic Symmetric Operator (in Second-quantization Calculations) |
| NGPSA | Natural Gas Pipeline Safety Act |