| Abbreviation | Definition |
|---|---|
| ASC | Acid Scratch Competition |
| ASCI | Advanced Structural Chemical Imaging |
| ASCI | Advances in Structural Chemical Imaging |
| ASD | Atomic Spin Density |
| ASE | Accelerated Solvent Extraction |
| ASH3 | Arsine |
| ASIT | Applied Signal And Image Technology |
| ASL | Atom Specification Language |
| ASMN | Activated Sludge Model for Nitrogen |
| ASP | ASPartate |
| ASPC | Accelerated Studies in Physics and Chemistry |
| ASPU | Acid Stable Pullulanase Units |
| ASR | Alkali-Silica Reaction |
| ASR | Analyte Specific Reagent |
| ASR | Atomic Sequential Reduction |
| ASTPT | ASTerriquinone PrenylTransferase |
| ASU | Air Separation Unit |
| ASW | Artificial Sea Water |
| AT | Adenine and Thymine |
| AT | Alkaline Transition |