smog

noun

ˈsmäg 

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

smogless

ˈsmä-gləs 

ˈsmȯ-

adjective

Synonyms of smog

• haze
• fog
• cloud
• mist

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 streets of New York were lined with snowdrifts stained black by soot, smog, and Model T motor oil. —Literary Hub, 17 Dec. 2025

The area includes 17 industrial facilities and the air quality was deemed unhealthy due to smog even before the construction of the billionaire’s supercomputer, according to Politico. —Sam Gillette, PEOPLE, 16 Dec. 2025

Dense toxic smog in India’s capital led to hundreds of flight cancellations and triggered travel advisories. —J.d. Capelouto, semafor.com, 15 Dec. 2025

An April report ranked the Washington/Baltimore/Arlington region as the 36th worst in the country and second worst in the mid-Atlantic region for ozone smog. —Jt Moodee Lockman, CBS News, 12 Dec. 2025

Word History

Etymology

smoke + fog

First Known Use

1880, in the meaning defined above

Phrases Containing smog

• anti-smog

Rhymes for smog

• blog
• bog
• clog
• cog
• dog
• flog
• fog
• frog
• grog
• hog
• jog
• log

Kids 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

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