| Abbreviation | Definition |
|---|---|
| ILV | Indicative Limit Values |
| IMA | Ideal Mechanical Advantage |
| IMB | Irvine / Michigan / Brookhaven experiment |
| IMC | Integrated Magnetic Concentrator |
| IMD | Interactive Molecular Dynamics |
| IMF | Intermediate Mass Fragments |
| IMPEC | Integrated Mathematics Physics Engineering And Chemistry |
| IMPETUS | Integrated Math and Physics for Entry to Undergraduate STEM |
| IMRT | Intensity-modulated Radiation Therapy |
| IMSP | Institute of Mathematical Sciences and Physics |
| INAA | Instrumental Neutron Activation Analysis |
| IND | Induced Nuclear Disintegration |
| inf. | infinity |
| ING | Intense Neutron Generator |
| INP | Institute of Nuclear Physics |
| INPE | National Space Research Institute (Brazil) |
| INS | Inelastic Neutron Scattering |
| INS | Ion-Neutralization Spectroscopy |
| INVAR | Invariable (metal alloy) |
| IO | Interactive Optimum |