| Acronym | Meaning |
| STEAMER | Slow Turning Echo Amplitude Modulation And Echo Reduction |
| STECS | Solar Thermal Electric Conversion Systems |
| STEL | Short Term Exposure Limit |
| STEM | Scaled Taylor Exponential Model |
| STEM | Scanning Transmission Electron Microscopy |
| STEP | Science And Technology For Environmental Protection |
| STEP | Solar Terrestrial Energy Program |
| STEP | Stratosphere Troposphere Exchange Project |
| STEP | Soil Treatment Evaluation Program |
| STERAO | Stratosphere-Troposphere Experiments: Radiation |
| STEREO | Solar TErrestrial RElations Observatory |
| STF | Slater-type Function |
| STFT | Short Time Fourier Transform |
| STHF | Single-term Hartree-Fock |
| STHM | Scanning Thermal Microscopy |
| STI | Shallow Trench Isolation |
| STIB | Stratosphere-Troposphere Interactions And The Biosphere |
| STIG | Steam-injected Gas Turbines |
| STIM | Scanning Transmission Ion Microscopy |
| STIRAP | Stimulated Raman Adiabatic Passage |
| STIS | Space Telescope Imaging Spectrograph |
| STJ | Superconducting Tunnel Junction |
| STLC | Soluble Threshold Limit Concentration |
| STLE | Society Of Tribologists And Lubrication Engineers |
| STLS | Singwi-Tosi-Land-Sjolander (generalized Random-phase Approxn. For Effective Pair Potentials Of Liq. Metals) |
| STM | Scanning Tunneling Microscopy |
| STM | Space-translation Method (in Atomic Collision Calcn.) |
| STM | Symptom Tree Model |
| STMAS | Satellite Transition Magic-angle-spinning |
| STMCTDHF | Spin-tensor Multiconfigurational Time-dependent Hartree-Fock |
| STMT | Superplastic Thermomech. Treatment |
| STN | Scientific And Technical Information Network |
| STN | Subthalamic Nucleus |
| STN | Super Twisted Nematic |
| STNAA | Short Time Neutron Activation Analysis |
| STO | Slater-type Orbital |
| STO NG | (n = A Number) Slater Type Orbitals Obtained By Using N Gaussian Functions |
| STOAT | Sewage Treatment Operation And Analysis Over Time [model] |
| STOCSY | Statistical Total Correlation Spectroscopy |
| STODI | Slater-type Orbital-point Dipole Interaction (in Mol. Polarizability Calcns.) |
| STOIC | Stratospheric Ozone Intercomparison Campaign |
| STOIIP | Stock Tank Oil Initially In Place |
| STOL | Short Take-Off And Landing |
| STOM | Scanning Tunneling Optical Microscopy |
| STORET | Storage And Retrieval Of U.S. Waterways Parametric Data |
| STORMS | Nevada Study And Tests Of The Release Of Mercury From Soils |
| STOVL | Short Take-Off And Vertical Landing |
| STP | Slater-transform-preuss (wave Functions) |
| STP | Sewage Treatment Plant |
| STP | Similarity Transformation (based) Perturbation (theory) |