| Abbreviation | Definition |
|---|---|
| STCW | Standards of Training, Certification and Watchkeeping |
| STD | Salinity, Temperature, and Depth |
| STEP | Salmon Trout Enhancement Program |
| STEP | Stratosphere-Troposphere Exchange Project |
| STK | Stephens Creek, Australia seismograph station |
| STK | Stickey (quality of bottom on nautical charts) |
| STMW | Subtropical Mode Water |
| STOA | Shock Time-Of-Arrival |
| STORM | Stormscale Operational and Research Meteorology |
| STORM-FEST | STORM Fronts Experiment Systems Test |
| STP | Science and Technology Policy |
| STREAM | Salmon Trout Restoration Education and Aquatic Management |
| STS | Science, Technology, and Society |
| STT | Small Tactical Terminal |
| STUW | Subtropical Underwater |
| STUW | Sub-Tropical UnderWater |
| SU | Sea Urchin |
| SUAVE | Submersible system Used to Assess Vented Emissions |
| SUBS | Submerges |
| SURFRAD | Surface Radiation |