What is the meaning of Miasma?

A noxious atmosphere or emanation once thought to originate from swamps and waste, and to cause disease.

A noxious atmosphere or influence, an ominous environment.

miasma (noxious atmosphere or influence)

miasma (emanation from rotting organic matter causing diseases)

miasma (noxious atmosphere from swamps)

miasma

miasma (noxious atmosphere or influence)

miasma (noxious emanation from swamps that was thought to cause diseases)

miasma

Source: wiktionary.org