| Abbreviation | Definition |
|---|---|
| IAC | Interface Adapter Unit |
| IAC | Interplanetary Alien Control |
| IACS | Inertial Attitude Control System |
| IAD | Interface Agreement Document |
| IAD | Interface Analysis Document |
| IAL | Immediate Action Letter |
| IAL | International Algebraic Language |
| IAM | International Association of Machinists |
| IandC | Instrument and Communication |
| IandC | Instrumentation and Communication |
| IAP | Information Assessment Process |
| IARS | Independent Air Revitalization System |
| IAS | Impact Assessment Sheet |
| IAS | Indicated AirSpeed |
| IAS | Inertial Active System |
| IAS | Institut d'Astrophysique Spatiale, France |
| IAS | Integrated Avionics System |
| IASS | Inverter/ATCS Support Structure |
| IAT | Intake Air Temperature |
| IAT | Integrated Avionics Test |