| Abbreviation | Definition |
|---|---|
| ISI | International Sensitivity Index |
| ISIL | Intelligence Systems Integration Laboratory |
| ISL | Illinois Simulator Laboratory |
| ISL | Information Systems Laboratories |
| ISL | Intelligent Systems Laboratory |
| ISL | International Standard for Laboratories |
| ISMRM | International Society for Magnetic Resonance in Medicine |
| ISOC | Integral Science Operations Centre |
| ISPE | International Society for Pharmaceutical Engineering |
| ISPL | Intelligent Signal Processing Laboratory |
| isq | insufficient quantity |
| ISRAC | Israel Laboratory Accreditation Authority |
| ISSL | Information Systems Security Laboratory |
| ISSL | Intelligent Signal Systems Laboratory |
| ISSL | Intelligent Structures and Systems Laboratory |
| ISSL | Interface and Surface Science Laboratory |
| ITAM | Immunoreceptor Tyrosine-based Activation Motif |
| ITD | Intra-type differentiation |
| ITI | Inter-Trial Interval |
| ITL | inGenious Targeting Laboratory |