| Acronym | Meaning |
| RSPT | Rayleigh-Schroedinger Perturbation Theory |
| BLR | Broad Line Region |
| LCDA MO | Linear Combination Of Donor-acceptor Molecular Orbital Theory |
| UPF | UV Protection Factor |
| HASL | Hypothetical Active Site Lattice |
| EEM | Elastic Emission Machining |
| SGGA | Symmetric Group Graphical Approach (in CI Calcns.) |
| CTBT | Comprehensive Test Ban Treaty |
| 3A | Alumina Aluminide Alloys |
| NEAR | Near Earth Asteroid Rendezvous |