| Acronym | Meaning |
| NGO | Nongovernment Organization(s) |
| NSSS | Nuclear Steam Supply System |
| RASSI | Restricted Active Space State Interaction |
| MEV | Mink Enteritis Virus |
| NWSIA | National Water Supply Improvement Association |
| CGO | Configuration Generating Orbital (a Type Of MO) |
| SCSRC | Solids Contact Slurry Recirculating Clarifier(s) |
| B1B | (coulomb) Boundary-corrected First Born (for Scattering) |
| NSTX | National Spherical Torus Experiment |
| MLCPA | Maximum Likelihood Principal Component Analysis |