| MARC | machine-readable cataloging; multifocal and recurrent choroidopathy |
|---|---|
| MRAB | machine-readable archives in biomedicine |
| MRI | machine-readable identifier; magnetic resonance imaging; medical records information; Medical Resear... |
| MSMAID | machine, suction, monitor, airway equipment, intravenous line, drugs [for bronchoscopy] |
| A2 P2 | aortic second sound; pulmonary second sound |