| Acronym | Meaning |
| SAIM | Scaled Atoms-in-molecules |
| SAIS | Science And Applications Information System |
| SALCCSD | Spin-adapted Linear Coupled-cluster (with) Single And Double Excitations) |
| SALD | Selective Area Laser Deposition |
| SALDI | Surface-assisted Laser Desorption/ionization |
| SALI | Secondary Atom Laser Ionization |
| SALQR | Successive Approximation Linear Quadratic Regulator (for Groundwater Management) |
| SALS | Small-angle Light Scattering |
| SALSA | Scoring Algorithm For Spectral Analysis |
| SAM | Scanning Auger Microscopy |
| SAM | Sterile Alpha Motif |
| SAM | Stratospheric Aerosol Monitor |
| SAM | Scanning Acoustic Microscopy |
| SAM | Self-assembled Monolayer |
| SAM1 | Semi-ab Initio Model1 |
| SAMA | Scientific Apparatus Makers Association |
| SAMBA | Satellite For Measurement Of Background Anisotropies |
| SAMHSA | Substance Abuse And Mental Health Services Administration |
| SAMI | Southern Appalachian Mountains Initiative |
| SAMMS | Self-assembled Monolayers On Mesoporous Supports |
| SAMO | Simulated Ab Initio Molecular Orbital |
| SAMOS | System For Automated Monitoring Of Org. Pollutants In Surface Water |
| SAMPE | Society For The Advancement Of Material And Process Engineering |
| SAMPEX | Solar Anomalous And Magnetospheric Particle Explorer (spacecraft) |
| SAMPL | Selective Amplification Of Microsatellite Polymorphic Loci |
| SAMS | Stratospheric And Mesospheric Sounder |
| SAMSON | Severe Accident Management System Online Network |
| SAN | Styrene-acrylonitrile Copolymer |
| SANDER | Simulated Annealing With NMR-derived Energy Restraints |
| SANDS | Stratospheric Aitken Nuclei Detection System |
| SANO | Symmetry-adapted Natural Orbital |
| SANS | Small-angle Neutron Scattering |
| SAP | Scientific Advisory Panel (FIFRA) |
| SAP | Sampling And Analysis Program |
| SAPHIR | Spectrometer Arrangement For Photon Induced Reactions |
| SAPK | Stress-activated Protein Kinase |
| SAPRC | Statewide Air Pollution Research Center |
| SAPS | Spherical Average Pseudopotential |
| SAPT | Symmetry-adapted Perturbation Theory |
| SAPW | Symmetrized Augmented Plane Wave |
| SAQM | SARMAP Air Quality Model |
| SAR | Structure-Activity Relationship |
| SAR | Synthetic Aperture Radar |
| SAR | Sequential Adiabatic Reduction |
| SAR | Simulated Acidic Rain |
| SAR | Sodium Absorption Ratio |
| SARA | Smad Anchor For Receptor Activation |
| SARA | Saturates |
| SARA | Superfund Amendments And Reauthorization Act Of 1986 |
| SARAH | System For Advising On The Regulations For Assessing Hazards |