macro- [from Greek makros long, tall, high, large] Large, long, big (macroevolution, macrophage).

mal- or male- [Latin mal bad, evil, wicked; ugly] Bad(ly), evil(ly), poor(ly), abnormal(ly) (malpresentation).

mast- or masto- [from Greek mastos breast, udder] Breast, udder (mastology).

medi- or medio- [from Latin medius middle, middle of, mid, neutral, ordinary] In the middle (mediocarpal).

medull- or medullo- [from Latin medius marrow, innermost part] Denotes marrow (medullitis).

meg- or mega- or megal- or megalo- [from Greek megas, megale big, great, full-grown, vast, high] (1) great, large (megadont, megalocephaly); (2) one million (megamole).

melan- or melano- [from Greek melas, melan- dark, black, murky] Black, dark (melanosome).

mening- or meningio- [from Greek meninx membrane] Relating to the meninges (meningitis).

mer- or mero- [from Greek meros share, portion, part] Part, partial, segmented (merozoite).

mero- [from Greek meros thigh, femur] Denotes the thigh (merocoxalgia).

mes- or meso- [from Greek mesos middle, in the middle] (1) middle (mesoderm, Mesozoic); (2) mesentery (mesoileum).

met- or meta- or meto- [from Greek meta among, between, after, later, along with] (1) occurring after, succeeding (metagenesis); (2) beyond (metacarpus); (3) behind, posterior (metencephalon); (4) later, more advanced (Metazoa); (5) across (metoxenous); (5) chemistry: in meta-substitution, the substituents occupy positions 1 and 3 (see explanatory diagram>>).

metall- or metallo- [from Latin metallum metal] Denotes metal(s) (metallophobia).

metop- or metopo- [from Greek metopon brow, forehead] Forehead (metopodynia).

metr- or metra- or metro- [from Greek metra uterus] Relating to the uterus, uterine (metritis, metrocarcinoma).

micro- [from Greek mikros small] (1) small; (2) one millionth (microliter).

milli- [from Latin mille thousand] One thousandth (milliliter).

mid- [from Old English midd middle] Middle, in the middle (midlands, mid-incisor).

milli- [from Latin mille thousand] One thousandth (milliliter).

mi- or mio- or meio- [from Greek meion less] Less, smaller, reduction (Miocene, meiosis).

mit- or mito- [from Greek mitos thread] (1) thread (mitochondrion, mitosis) (2) mitosis (mitoinhibitory).

mis- [from Old English mis-] Incorrect(ly), improper(ly) (misclassification).

mis- or miso- [from Greek misos hatred] Hatred (misogynist).

mon- or mono- [from Greek monos alone, solitary] Single (monocotyledon, monocyte, monoecious, monosaccharides, monosomy, monotreme).

morph- or morpho- [from Greek morphe form, shape, kind, sort] Form, shape, type, structure (morphology).

muc- or muco- [from Latin mucus mucus, snot] Pertaining to mucous or mucous membrane (mucigen).

multi- [from Latin multus many] Many (multiplexing).

muscul- or musculo- [from Latin musculus muscle] Pertaining to muscle (musculocutaneous).

my- or myo- [from Greek myon muscle] Of or relating to muscle (myoatrophy, myalgia).

myc- or myco- [from Greek mykes mushroom] Fungus, mushroom (Mycobacterium, mycology, mycosis).

myel- or myelo- [from Greek myelos marrow] (1) of or relating to marrow (myelocyte); (2) relating to the spinal cord (myelodysplasia)

myri- or myria- or myrio- [from Greek myrioi ten thousand] Countless, extremely numerous (myriapod).

myria- [from Greek myrioi ten thousand] Ten thousand (myriameter).

myx- or myxo- [from Greek myxa mucus] Of or relating to mucus or slime (myxobacterium).