the.com/miasma
The medieval theory that bad air, not germs, caused disease — confidently wrong for centuries.
means A foul or unwholesome vapor, or the discredited belief that such air spread illness.
from From Greek miasma, pollution or stain, from miainein, to defile — bad smells took the blame before microscopes set the record straight.
Cholera scapegoatBlamed stinky air until John Snow blamed the water.
Modern useNow any oppressive cloud, literal or moral.
Linguistic cousinShares roots with miscreant ideas of contamination.