| Abbreviation | Definition |
|---|---|
| APTH | 1-Acetyl-3-Phenylamidine Thiocarbamide Hydrochloride |
| APTMS | Aminopropyltrimethoxysilane |
| APU | Acid Purification Unit |
| APV | 2-Amino-5-PhosphonoValerate |
| AQBC | Aminoguanidine Bicarbonate |
| AQL | Acceptable Quality Limits |
| AQL | Average Quality Level |
| AR | Acid Rain |
| AR | Analytical Reagent |
| Ar | Argon |
| ARCHER | At Risk Chemical Health Education and Resiliency |
| ARD | Accelerated Rehabilative Disposition |
| ARL | Axiom Right Left |
| ARP | Acid Rain Program |
| ARSR | Acid Reflux Sniper Rally |
| AS | Ammonium Sulphate |
| ASA | Acetyl Salicylic Acid |
| ASA | acetylsalicylic acid (ASPIRIN) |
| ASA | Alkenyl Succinic Anhydride |
| ASBC | American Society of Brewing Chemists |