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

• 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

Uncertainty hung over this season like a layer of smog over a mid-tier city. —Brian Moylan, Vulture, 31 Oct. 2025

And in Tennessee’s South Memphis, the methane gas turbines that power an xAI data center give off air pollutants contributing to smog and formaldehyde. —Natalie Kainz, NBC news, 28 Oct. 2025

One is reminded of the chemical smog that grants us such vibrant sunsets; who ever said the end of the world wouldn’t be beautiful? —Justin Chang, New Yorker, 24 Oct. 2025

On Tuesday, the day after a night of Diwali celebrations, New Delhi woke up to a shroud of smog. —Robert Birsel, MSNBC Newsweek, 21 Oct. 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