: 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
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
The Adams administration is making swift, intentional investments, building smart to protect all New Yorkers from harsh rains, blazing sun and smog.
—
Meera Joshi, New York Daily News, 9 Feb. 2025
Delhi, a sprawling city of some 20 million people, faces huge issues like access to housing and high levels of air pollution that blanket the city in toxic smog for months each year.
—Jay Ganglani, CNN, 9 Feb. 2025
For instance, scenes of Wei and his friend swimming in a river, with skyscrapers — and smog — looming large in the background, provide a fluidity to the real-world that contrasts nicely with the heaviness of the simulated one.
—Beandrea July, IndieWire, 25 Jan. 2025
White families began to flee the area, driven by freeway construction, hillside smog and societal developments like the civil rights movement, school integration and the Watts Riots, the group said.
—Marc Ramirez, USA TODAY, 18 Jan. 2025
See all Example Sentences for smog 
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Meera Joshi, New York Daily News, 9 Feb. 2025
Delhi, a sprawling city of some 20 million people, faces huge issues like access to housing and high levels of air pollution that blanket the city in toxic smog for months each year.
—Jay Ganglani, CNN, 9 Feb. 2025
For instance, scenes of Wei and his friend swimming in a river, with skyscrapers — and smog — looming large in the background, provide a fluidity to the real-world that contrasts nicely with the heaviness of the simulated one.
—Beandrea July, IndieWire, 25 Jan. 2025
White families began to flee the area, driven by freeway construction, hillside smog and societal developments like the civil rights movement, school integration and the Watts Riots, the group said.
—Marc Ramirez, USA TODAY, 18 Jan. 2025
See all Example Sentences for smog
Dictionary Entries Near smog
Cite this Entry
“Smog.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/smog. Accessed 22 Feb. 2025.
Copy CitationKids Definition
smog
noun
ˈsmäg 
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
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