smog

noun

ˈsmäg How to pronounce smog (audio)
ˈsmȯg
Synonyms of smognext
: a fog made heavier and darker by smoke and chemical fumes
also : a photochemical haze caused by the action of solar ultraviolet radiation on atmosphere polluted with hydrocarbons and oxides of nitrogen especially from automobile exhaust
smogless
ˈsmä-gləs How to pronounce smog (audio)
ˈsmȯ-
adjective

Synonyms of smog

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Examples of smog in a Sentence

the city's smog was once so bad that darkness often prevailed, even at noon
Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
What was once the season of patios and long days has increasingly turned into one of heat advisories, wildfire smoke, and smog alerts. — Alexandra Emanuelli, Travel + Leisure, 28 June 2026 For decades, the United States made steady progress in reducing surface ozone pollution, the main ingredient in smog. — Meng Zhou, The Conversation, 4 June 2026 Not only that, but California has very specific fuel specifications aimed at minimizing smog. — Matt Egan, CNN Money, 17 June 2026 Huxley added heatwaves are usually caused by high air pressure systems, leading to less air movement and increasing the build-up of air pollution, with methane and other pollutants reacting to create ground-level ozone – a component of smog. — Jamie Hailstone, Forbes.com, 19 June 2026 See All Example Sentences for smog

Word History

Etymology

smoke + fog

First Known Use

1880, in the meaning defined above

Time Traveler
The first known use of smog was in 1880

Phrases Containing smog

Rhymes for smog

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Browse Nearby Words

smock mill
smog
smoggy
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Cite this Entry

“Smog.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/smog. Accessed 7 Jul. 2026.

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Kids Definition

smog

noun
ˈsmäg How to pronounce smog (audio)
also ˈsmȯg
: a thick haze caused by the action of sunlight on air polluted especially by smoke and automobile exhaust fumes
Etymology

from smoke and fog

Medical Definition

smog

noun
ˈsmäg also ˈsmȯg
: a fog made heavier and darker by smoke and chemical fumes
also : a photochemical haze caused by the action of solar ultraviolet radiation on atmosphere polluted with hydrocarbons and oxides of nitrogen especially from automobile exhaust

More from Merriam-Webster on smog

Nglish: Translation of smog for Spanish Speakers

Britannica.com: Encyclopedia article about smog

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