| Abbreviation | Definition |
|---|---|
| A | Absorptivity |
| A | Aqueous |
| A | Atom |
| A/CNK | Al2O3/( CaO + Na2O + K2O) ( Shands Index) |
| A/CNK | Al2O3/(CaO + Na2O + K2O) (Shands Index) |
| A/V | Alcohol per Volume |
| AA | Acetic Acid |
| AA | Activation Analysis |
| AA | Advanced Alloy |
| AA | Amino Acid |
| AA | Amino Acrylate |
| AA | Arachidonic Acid |
| AA | Ascorbic Acid |
| AAAD | Aromatic Amino Acid Decarboxylase |
| AAAD | Aromatic L amino acid decarboxylase |
| AAAD | Aromatic l-Amino Acid Decarboxylase |
| AAAH | Aromatic Amino Acid Hydroxylases |
| AAAO | Aromatic Amino Acid Oxidase |
| AAAP | Amino Acid Auxin Permease |
| AAC | Aluminum Aluminum Chrome |