| Acronym | Meaning |
| ASAXS | Anomalous Small-angle X-ray Scattering |
| ASB | Ambient Stds. Branch [of The US EPA] |
| ASB | Aerobic Stabilization Basin |
| ASBF | Aerated Submerged Biological Filter |
| ASBMB | American Society For Biochemistry And Molecular Biology |
| ASBOW | Axial Spin Bond-order Wave |
| ASC | Ascorbic Acidpar |
| ASCA | Advanced Satellite For Cosmology And Astrophysics |
| ASCA | Automatic Subject Citation Alert |
| ASCB | American Society For Cell Biology |
| ASCE | American Society Of Civil Engineers |
| ASCEND | Advanced System For Computations In Engineering Design |
| ASCI | Accelerated Strategic Computing Initiative |
| ASCII | American Standard Code For Information Interchange |
| ASCO | American Society Of Clinical Oncology |
| ASCOT | Atmospheric Studies In Complex Terrain |
| ASCREV | Anodic Stripping Continuous Recall Enhancement Voltammetry |
| ASCT | Autologous Stem Cell Transplantation |
| ASCW | Axial Spin Current Wave (type Of Hartree-Fock Wave Function) |
| ASD | Active Subslab Soil Depressurization (for Radon Minimization In Buildings) |
| ASDES | Aircraft Sensor Data For The Earth Sciences |
| ASDEX | Axially Symmetric Divertor Expt. |
| ASDW | Axial Spin Density Wave |
| ASDWA | Association Of State Drinking Water Administrators |
| ASE | Aromatic Stabilization Energy |
| ASE | Accelerated Solvent Extraction |
| ASE | Activated Sludge Effluent |
| ASE | Amplified Spontaneous Emission |
| ASE | Augmented Secular Equation |
| ASEAN | Assocn. Of South-East Asian Nations |
| ASEC | Applied Solar Energy Corporation |
| ASECS | Antigen-specific Electrophoretic Cell Separation |
| ASED | Atom Superposition-electron Delocalization |
| ASEHF | Approximate Spin-extended Hartree-Fock |
| ASEMP | Active Sites Environmental Monitoring Program |
| ASF | African Swine Fever |
| ASF | Air Sea Fluxes |
| ASF | Atomic Sensitivity Factor |
| ASF | Augmented-space Formalism (a Generalization Of CPA) |
| ASFF | Aerated Stationary Or Submerged Fixed-film (wastewater Treatment) |
| ASFV | African Swine Fever Virus |
| ASGDI | Atmospheric Sampling Glow Discharge Ionization |
| ASGP | Aerobic Suspended Growth Process |
| ASH | Air-sparged Hydrocyclone |
| ASHAA | Asbestos School Hazard Abatement Act |
| ASHES | Axial Seamount Hydrothermal Emissions Study |
| ASHG | American Society Of Human Genetics |
| ASHI | American Society Of Histocompatibility And Immunogenetics |
| ASHOE | Airborne Southern Hemisphere Ozone Experiment |
| ASHP | American Society Of Health-System Pharmacists |