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

Light shone through the brown smog. —CNN Money, 15 Apr. 2026

It’s not typically used during the summer months because of concerns the higher ethanol concentration can worsen smog. —News Service Of Florida, Sun Sentinel, 14 Apr. 2026

Volatile organic compounds and carbon monoxide are the key ingredients in ground-level ozone pollution, which combine on hot days to create a smog that fouls the air. —Noelle Phillips, Denver Post, 9 Apr. 2026

Environmentalists are now raising alarm bells that the program is puttering out, which not only slows down progress with smog but also keeps the country more dependent on volatile energy imports at a time of growing geopolitical risk. —ABC News, 8 Apr. 2026

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