| Abbreviation | Definition |
|---|---|
| ER | Endoplasmic Reticulum |
| ER | Enhanced Response |
| ER | Euthansia Run |
| ER | External Rotation |
| ERA | Endometrial Resection and Ablation |
| ERD | Early Renal Disease |
| ERE | External rotation in extension |
| ERF | External rotation in flexion |
| ERGO | Energy Rich Glucose Optimized |
| ERGO | Euthanasia Research and Guidance Organization |
| ERGOT | Ergotamine Tartrate |
| ERK | Extracellular Regulated Kinase |
| ERK | extracellular signal-related kinase |
| ERN | Error Related Negativity |
| ERP | Effective Refractory Period |
| ERPC | Evacuation Of Retained Products Of Conception |
| ERS | Energy Releasing Stimulant |
| ERT | Estrogen Replacement Therapy |
| ERV | Endogenous RetroVirus |
| ERV | Expiratory Reserve Volume |