miasma

American  

[mahy-az-muh, mee-] / maɪˈæz mə, mi- /

noun

plural

miasmas, miasmata

1. noxious exhalations from putrescent organic matter; poisonous effluvia or germs polluting the atmosphere.

2. a dangerous, foreboding, or deathlike influence or atmosphere.

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miasma British  

/ mɪˈæzmə, ˌmiːəzˈmætɪk /

noun

1. an unwholesome or oppressive atmosphere

2. pollution in the atmosphere, esp noxious vapours from decomposing organic matter

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Other Word Forms

• miasmal adjective
• miasmatic adjective
• miasmatical adjective
• miasmic adjective
• unmiasmal adjective
• unmiasmatic adjective
• unmiasmatical adjective
• unmiasmic adjective

Etymology

Origin of miasma

1655–65; < New Latin < Greek míasma stain, pollution, akin to miaínein to pollute, stain

Explanation

A miasma is a cloud of foul-smelling vapor, like swamp gas. You could have a miasma of sweat that lingers in a locker room long after a soccer team has left, or a miasma of rumor swirling around a politician. As you've probably figured out, miasma is always negative. You could describe the miasma of a hot summer day, but you'd be thinking of the stench of uncollected garbage and exhaust fumes, not the smell of summer flowers. From the Middle Ages until the late 19th century, when germs were identified as causing disease, people believed that you could get sick from the miasma of everyday life — from the odors arising from poor sanitation and cramped quarters.

Example Sentences

There’s some truth to this, but the overarching emphasis on miasma theory fundamentally ignores how the immune system works.

From Salon • Nov. 29, 2025

The harvest of that change was an inaugural meeting of the new panel that was enveloped in a miasma of confused, uninformed debate.

From Los Angeles Times • Nov. 25, 2025

Few writers since Henry James can create an atmosphere of doubt around events and character as effectively as this author does, and in “Venetian Vespers” the miasma thickens at every turn.

From The Wall Street Journal • Oct. 9, 2025

It was a couple of weeks after the great smog had brought London to a standstill, and although that particularly foul miasma had dispersed, smog still regularly reduced visibility.

From BBC • Dec. 30, 2024

By the end of the war, scientists in Europe uncovered evidence that it was germs, not poisonous miasma, that attacked the body.

From "Ambushed!" by Gail Jarrow