| Acronym | Meaning |
| NIWG | National Interagency Work Group |
| GCLSDA | Gradient-corrected Local Spin Density Approximation |
| PSES | Pretreatment Standards For Existing Sources |
| MSS | Mobile Servicing Station [space Station] |
| BDNF | Brain-derived Neurotrophic Factor |
| OMIM | Online Mendelian Inheritance In Man |
| FERC | Federal Energy Regulatory Commission |
| CS | Compton Scattering |
| MMC | Metal-Matrix Composite |
| HCN | US Historical Climatology Network |