| Abbreviation | Definition |
|---|---|
| PPPL | Princeton Plasma Physics Laboratory |
| PPT | Parts Per Trillion |
| PPT | Precipitate |
| ppt. | precipitate |
| PPTL | Petroleum Products Testing Laboratory |
| PQA | Pharmaceutical Quality Assurance |
| PQG | Pharmaceutical Quality Group |
| PQSL | Produce Quality and Safety Laboratory |
| PR | Pathogen Resistant |
| PR | Progesterone Receptor |
| PR | prothrombin ratio |
| PRA | Plasma renin assay |
| PRCT | Prospective Randomized Controlled Trial |
| PRDT | Parent Role Development Theory |
| PRE | Progesterone Response Element |
| PREL | Pavement and Railroad Engineering Laboratory |
| PREL | Power Refrigeration And Electrical Laboratory |
| PRL | Physical Research Laboratory |
| PRL | Physicians Reference Laboratory |
| PRL | Physiology Research Laboratory |