| Abbreviation | Definition |
|---|---|
| SIM | Scientific Instrumentation Module |
| SIM | Simulate, Simulation |
| SIM | Simulator |
| SIM | Solar Irradiance Monitor |
| SIM | Space Interferometry Mission |
| SIMA | Small Incremental Motion Actuator |
| SIMAS | Shuttle Information Management Accountability System |
| SIMCOM | Simulation Complex |
| SIMFAC | Simulation Facility |
| SIMO | Simultaneously |
| SIMPLEX | Shuttle Ionospheric Modification with Pulsed Local Exhaust Experiment |
| SIMR | Systems Integration Management Review |
| SIMS | Shuttle Imaging Microwave System |
| SIMS | Shuttle Inventory Management System |
| SIMS | Still Image Management System |
| SIMU | Simulated Inertial Measurement Unit |
| SIN | Sine |
| SINDA | Systems Improve Numerical Differencing Analyzer |
| SIO | Serial Input/Output |
| SIO | Systems Integration Office |