| MEC | median effective concentration; middle ear canal; middle ear cell; minimum effective concentration |
|---|---|
| MFD | mandibulofacial dysostosis; midforceps delivery; milk-free diet; minimum fatal dose; multiple fracti... |
| min | mineral; minim; minimum, minimal; minor; minute |
| MIO | minimum identifiable odor; modular input/output |
| MLC | minimum lethal concentration; mixed leukocyte culture; mixed ligand chelate; mixed lymphocyte concen... |