| Acronym | Meaning |
| SA-CAS-SCF | State-averaged-complete Active Space-SCF |
| SA-LCAO | Symmetry-adapted Linear Combination Of Atomic Orbitals |
| SA-MCSCF | State Averaged Multiconfiguration Self-consistent Field (wave Function) (see Also ICF-CI) |
| SAA | Serum Amyloid A |
| SAACGS | State Ambient Air Concentration Guidelines Or Standards |
| SAAO | Symmetry-adapted Atomic Orbital |
| SAAP | Spin Adapted Antisymmetrized Product (in MC-SCF Theory) |
| SAB | Science Advisory Board (USEPA) |
| SAB | Substratum-aerated-biofilm Reactor |
| SABER | Sounding Of The Atmosphere Using Broadband Emission Radiometry |
| SABRE | Sweden And Britain Radar Experiment |
| SABS | South African Bureau Of Standards |
| SAC | Self-Aligned Contact |
| SAC | Spectral Absorption Coeff. |
| SAC | Symmetry-adapted Cluster (expansion Method For Calcg. Wave Functions) |
| SAC-CI | Symmetry-adapted Cluster Configuration Interaction (theory For Wave-function Expansion) |
| SACF | Symmetry-adapted Configuration Function |
| SACM | Superfund Accelerated Cleanup Model |
| SACM | Statistical Adiabatic Channel Method (in Ion-mol. Reactions) |
| SACRED | Silicon Array For ConveRsion Electron Detection |
| SAD | Selected Area Diffraction Patterns (crystal Chemistry) |
| SADP | Selected Area Diffraction Patterns |
| SADPT | Symmetry-adapted Double Perturbation Theory |
| SADT | Self Accelerating Decomposition Temperature |
| SADVR | Symmetry-adapted Discrete Variable Representation (in Mol. Wave Function Calcn. For Nuclear Motion On A Given PES) |
| SAE | Society Of Automotive Engineers |
| SAED | Selected Area Electron Diffraction |
| SAES | State Agricultural Experiment Stations |
| SAES | Scanning Auger Electron Spectroscopy |
| SAEST | Society For Advancement Of Electrochemical Science And Technology |
| SAF | Symmetry Adapted Function (in CI Calcns.) |
| SAFARI | Southern African Regional Science Initiative |
| SAFETI | Software For The Assessment Of Fire |
| SAFIR | Single Aperture Far-Infrared Observatory |
| SAFIR | Smoke Gas Anal. By Fourier Transform IR Spectroscopy |
| SAFIRE | Spectroscopy Of The Atmosphere Using Far Infrared Emission |
| SAFM | Scanning Acoustic Force Microscopy |
| SAFM | Scanning Attractive Force Microscopy |
| SAFT | Spark Analysis For Traces |
| SAFT | Statistical Assocg. Fluid Theory |
| SAFT-VR | Statistical Assocg. Fluid Theory For Chain Mols. With Interaction Potentials Of Variable Range |
| SAGA | Soviet American Gas And Aerosol Experiment |
| SAGE | Soviet-American Gallium Experiment |
| SAGE | Stratospheric Aerosol And Gas Experiment |
| SAGE | Serial Analysis Of Gene Expression |
| SAGE II | Stratospheric Aerosol And Gas Expt. II |
| SAGFET | Self-aligned Gate Field Effect Transistor |
| SAI | Simplified Ab Initio Method |
| SAI | Spline-fitted Ab Initio (potential Energy Surface) |
| SAIC | Science Applications International Corporation |