| Abbreviation | Definition |
|---|---|
| PEM | Protein Energy Malnutrition |
| PEMD | Primary Esophageal Motility Disorder |
| PEMQ | Prenatal Energy Mobilizing Qigong |
| PEMR | Post-Exercise Metabolic Rate |
| PEMR | Progressive Epilepsy with Mental Retardation |
| PEMS | Poult Enteritis Mortality Syndrome |
| PEN | PENicillin |
| PENS | Patterned Electrical Neuromuscular Stimulation |
| PENS | Percutaneous Electrical Nerve Stimulation |
| PENTOBARB | PENTOBARBital sodium |
| PEP | Peak Expiratory Pressure |
| PEP | PEPpermint |
| PEP | Positive Expiratory Pressure |
| PEP | Post Exposure Prophylaxis |
| PEPG | Plant Environmental Physiology Group |
| PEPPI | Perceived Efficacy in Patient Physician Interactions |
| PERL | Pupils Equally Responsive to Light |
| PERLA | Pupils Equal, Reactive to Light and Accommodation |
| PEROS | By mouth |
| PEROX | Peroxide |