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

• brume
• fog
• gauze
• haze
• mist
• murk
• reek
• soup

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

Ozone, a major component of smog, forms when sunlight triggers a reaction between nitrogen oxides and volatile organic compounds—both commonly emitted by vehicles, industrial facilities, and power plants. —Daniel R. Depetris, Newsweek, 25 Mar. 2025

Bringing classic cars to modern smog standards is costly, cumbersome and has driven a lot of the car-restoration industry to other states. —The Editorial Board, Orange County Register, 16 Mar. 2025

The greenhouse gas rating is 6, and the smog rating is 7; both out of 10. —Tony Leopardo, The Mercury News, 16 Mar. 2025

California can set such standards due to a clause in the 1970 Clean Air Act, written amid historic smog conditions in the Los Angeles region. —Sharon Udasin, The Hill, 13 Mar. 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