| Abbreviation | Definition |
|---|---|
| SHP | Shape |
| SHTF | Secondary Heat Transfer Fluid |
| SHTR | Standard Heat Transfer Rate |
| SI | Selectivity Index |
| SI | Slight Inclusion |
| SIAD | Synergistic Isogenous Activated Decontamination |
| SID | Spin Inverted Determinant |
| SIDOT | Speed Is Distance Over Time |
| sig | signal |
| SIM | Secondary Ion Mass |
| SIM | Selected Ion Monitoring |
| SIMOPS | Simultaneous Operations |
| SIMP | Strongly Interacting Massive Particle |
| SINP | Skobeltsyn Institute of Nuclear Physics |
| SIP | Simulations In Physics |
| SIR | Selective Internal Radiation |
| SITP | Stanford Institute for Theoretical Physics |
| SKA | Severe Kinetic Analyser |
| SKIN | Synth Kinetic Interface Nano |
| SKL | Servo Kinetic Laser |