| Abbreviation | Definition |
|---|---|
| MRA | Magnetic Resonance Analyser |
| MRA | Magnetic Resonance Angiography |
| MRC | Mitral Ring Calcification |
| MRC | Multilocular Renal Cyst |
| MRCP | Membership of the Royal Colleges of Physicians |
| MRD | Mucus Retaining Deficiency |
| MREP | Mount Rainier Emergency Physicians |
| MRG | Murmurs, Rubs, or Gallops |
| MRHD | maximum recommended human dose |
| MRL | Minimum Risk Level |
| MRO | Muscle Receptor Organ |
| MRS | Mentally Retarded Severe |
| MRSA | Methicillin Resistant Staphylococcus Aureus |
| MRSS | Modified Rodnan Skin Score |
| MRV | Magnetic Resonance Venography |
| MS | Mainstream Smoke |
| MS | Many Symptoms |
| MS | Medical Student |
| MS | Menstrual Syndrome |
| MS | Milisecond |