| Acronym | Meaning |
| BSRT | Biological Solids Retention Time |
| CLIPS | Chemical List Index And Processing System |
| OFPT | Operator Form (of) Perturbation Theory |
| UMTRCA | Uranium Mill Tailings Radiation Control Act |
| OSWER BBS | OSWER Electronic Bulletin Board System (see CLU-IN) |
| NLXC | Nonlocal Exchange Correlation (potential) |
| CMOS | Complementary Metal Oxide Semiconductor |
| WATR | Water Attenuation By Transverse Relaxation |
| TEMIS | Total Emissions Model For Integrated Systems |
| ISM | Intersecting Spheres Model (for Electronic-structure Calcns.) |