| Acronym | Meaning |
| TLS | Two-level System (with Tunneling Transitions Between Wells Of Double-well Potential) |
| FNAA | Fast Neutron Activation Analysis |
| UNESCO | United Nations Educational |
| INEGA | Instituto Nacional De Estadistica |
| NELC | Non-exclusion Liquid Chromatography |
| TIA | Transient Ischemic Attack |
| ARSCF | Approximate Relativistic SCF |
| QSRR | Quantitative Structure-retention Relationships |
| RFA | Regulatory Flexibility Analysis |
| ALMS | Atomic Line Molecular Spectroscopy |