| Abbreviation | Definition |
|---|---|
| Pa | Protactinium |
| PA | Proton Affinity |
| PAA | Phosphoric Acid Anodize |
| PAA | Phosphoric Acid Anodized |
| PAA | PolyAcrylic Acid |
| PAA | Polyacrylic Acid And |
| PAAP | Platelet Aggregation-Associated Protein |
| PABA | Para Amino Benzoic Acid |
| PABA | paraminobenzoic acid |
| PABLO | Perfect Alignment By Lateral Oxidation |
| PAC | Pharmaceutically Active Compound |
| PAC | Photoactivated Adenylyl Cyclase |
| PAC | Polycyclic Aromatic Content |
| PAC | Powdered Activated Carbon |
| PACE | Process Analytical Control Equipment |
| PACN | Pan Africa Chemistry Network |
| PACN | Pan African Chemistry Network |
| PACS | A Photo Advancing And Chemical Storage |
| PADRE | Partnership for Acid Drainage Remediation in Europe |
| PAFC | Phosphoric Acid Fuel Cell |