Do you know ghouls from goblins and ghosts?
1660s, from Modern Latin miasma "noxious vapors," from Greek miasma (genitive miasmatos) "stain, pollution, defilement, taint of guilt," from stem of miainein "to pollute," from possible PIE root *mai- "to stain, soil, defile" (cf. Old English mal "stain, mark," see mole (n.1)). Earlier form was miasm (1640s), from French miasme. Related: Miasmatic; miasmal.