| Term | Definition |
| macro- | large |
| macul/o | spot |
| mal- | bad, deficient |
| -malacia | softening |
| mamm- | breast |
| mamm/o | breast |
| mandibul/o | mandible (lower jaw bone) |
| -mania | obsession with |
| -masesis | chewing, mastication |
| mast/o | breast |
| mastoid/o | rounded protrusion of bone behind the ear |
| maxill/o | upper jawbone formed from the fusion of two maxillary bones |
| meat/o | a natural opening |
| medi/o | middle |
| medull/o | medulla, marrow |
| mega- | large, great |
| -megaly | enlargement |
| mel/o | limb |
| melan/o | black, dark |
| meli- | honey, sugar |
| men/o | menstruation, menses |
| mening/o | membranes |
| ment/o | mind |
| -mer | smallest unit of a repeating structure, member of a particular group |
| mer/o | part, partial |
| mes- | middle, mean |
| meso- | middle |
| meta- | beyond, change |
| -meter | measurement, instrument to measure |
| method/o | procedure, technique |
| metr/o | uterus (womb) |
| -metry | to measure |
| micro- | small |
| milli- | one thousandth |
| -mimesis | imitation, simulation |
| mio- | smaller |
| mis/o | opposite, aversion |
| -mnesia | memory |
| mogi- | difficult |
| mon/o | single, one |
| morph/o | shape, form |
| mort/o | death |
| mot- | move |
| -motor | motion |
| muc/o | mucus |
| multi | many, much |
| muscul/o | muscle |
| my/o | muscle |
| myc/o | fungus |
| myel/o | spinal cord, bone marrow |
| myocardi/o | myocardium (heart muscle) |
| myring/o | tympanic membrane (eardrum) |
| myx/o | mucus |