1: a vaporous exhalation formerly believed to cause disease
also : a heavy vaporous emanation (see EMANATION sense 2) or atmospherea miasma of tobacco smoke
2: an influence or atmosphere that tends to deplete or corrupt freed from the miasma of poverty— Sir Arthur Bryant the enervating miasma of fear— The Times Literary Supplement (London)also: an atmosphere that obscures : FOG
Miasma theory was the scientific explanation for disease prior to germ theory. Miasma means ‘pollution’ but is a holistic word both physical and metaphysical. Miasma could emanate from swamps, night air, ships, dead bodies, ill-will and immorality. Prisons in particular were believed to generate a lot of Miasma due to the festering, forgotten people inside.