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

There are other exemptions as well, like if a diesel truck has a gross vehicle weight rating over 14,000 pounds, like a massive Ford F-350 dually, doesn’t need smog testing. — Kyle Cheromcha, The Drive, 24 Sep. 2026

The elevation differences cause temperature inversions, where the warm air traveling over the ridges traps the cooler air closer to the ground, along with the smog and pollution. — Daliah Singer, Condé Nast Traveler, 22 Sep. 2026

The summer blend is meant to help limit the chances of smog in the Metro Detroit area. — Paula Wethington, CBS News, 18 Sep. 2026

The legislation expands smog check exemptions for certain collector cars that have been relegated to driveways and garages due to the challenge of passing a smog check. — Daniel Hernandez, Los Angeles Times, 17 Sep. 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