myelinisation vs. myelinization
marginalisation vs. marginalization
masculinisation vs. masculinization
masculinization vs. virilization
malnourishment vs. undernourishment
monochromacy vs. monochromatism
miserableness vs. wretchedness
macrocephaly vs. megalocephaly
microcephalus vs. microcephaly
monosaccharide vs. monosaccharose