| Acronym | Meaning |
| ATDC | After Top Dead Center (gasoline And Diesel Engine Timing) |
| ILIAC | International Library Information And Analytical Center |
| APA | Alkaline Phosphatase Activity |
| ISFSI | Independent Spent Fuel Storage Installation |
| MWCO | Molecular Weight Cut-off (in Membrane |
| FVVM | Finite Volume Variational Method (for Mol. Calcns.) |
| GCTM | Global Chemical Transport Model |
| RIOSA | Rotational Infinite Order Sudden Approxn. |
| CAIRA | Chemical Accident/incident Response And Assistance |
| ANNNI | Axial Next-nearest-neighbor Ising (model Of Superstructure) |