| Acronym | Meaning |
| GMAD | Geometric Mean Aerodynamic Diameter |
| PHF | Perturbative Hartree-Fock |
| RSS | Recombination Signal Sequence |
| NEMI | National Environmental Methods Index |
| NPC | Nuclear Pore Complex |
| CVO | Canonical Virtual Orbital |
| EOS | Earth Observing System |
| DPUMPN | Double-annihilation Procedure Unrestricted Moeller-Plesset Nth-order |
| CASE | Computer Aided Software Engineering |
| UNECE | United Nations Economic Commission For Europe |