\ ˈfȯg How to pronounce fog (audio) , fäg \

Definition of fog

 (Entry 1 of 2)

1a : vapor condensed to fine particles of water suspended in the lower atmosphere that differs from cloud only in being near the ground
b : a fine spray or a foam for firefighting
2 : a murky condition of the atmosphere or a substance causing it
3a : a state of confusion or bewilderment spent the morning in a fog
b : something that confuses or obscures hid behind a fog of rhetoric
4 : cloudiness or partial opacity in a developed photographic image caused by chemical action or stray radiation


fogged; fogging

Definition of fog (Entry 2 of 2)

transitive verb

1 : to cover, envelop, or suffuse with or as if with fog fog the barns with pesticide
2 : to make obscure or confusing accusations which fogged the real issues
3 : to make confused
4 : to produce fog on (something, such as a photographic film) during development

intransitive verb

1 : to become covered or thick with fog
2a : to become blurred by a covering of fog or mist
b : to become indistinct through exposure to light or radiation

Keep scrolling for more

Other Words from fog


fogless \ ˈfȯg-​ləs How to pronounce fog (audio) , ˈfäg-​ \ adjective

Synonyms & Antonyms for fog

Synonyms: Noun

Synonyms: Verb

Antonyms: Verb

Visit the Thesaurus for More 

Examples of fog in a Sentence

Noun Heavy fog made it difficult to see the road. a climate marked by heavy fogs The fog reduced visibility to a quarter of a mile. This problem has me in a fog. Verb The steam from the pot was fogging the window near the stove. The bathroom was all fogged up after my shower. politicians who try to fog the issue instead of taking a stand
See More
Recent Examples on the Web: Noun Such was the end, and the beginning, of formal legislative business Wednesday on Beacon Hill — an uncommon fog of action, even by the State House’s opaque standards. Globe Staff,, "Legislature begins new term just hours after finishing marathon meeting," 6 Jan. 2021 Once the fog burns away, skies should be partly sunny with a high temp of about 43. oregonlive, "Portland metro Monday weather: Sunny, cool, with windy conditions on east side; high 45," 28 Dec. 2020 There's also the prediction that fog in January brings a wet spring. Allison Chinchar, CNN, "New Year's Eve will be snowy in Central US while rain is forecast on Eastern Seaboard," 27 Dec. 2020 Just as on that storied eve when Rudolph demonstrated his usefulness as a navigational beacon for Santa, conditions here Thursday did include fog. Washington Post, "A Christmas Eve of wetness and warmth, but we have had warmer," 25 Dec. 2020 The forecast had looked worrisome throughout the week — rain had been predicted— but by the time the ensemble arrived at the Witte, the morning fog had burned off, leaving a crystal clear sky. Deborah Martin,, "New series of free outdoor classical music concerts will bring Agarita chamber ensemble to every San Antonio City Council district," 15 Dec. 2020 At least as much of a bang as a .22 pistol can make in a canyon smothered by fog. Keith Mccafferty, Field & Stream, "My Steelhead Addiction," 11 Dec. 2020 One of San Francisco’s greatest silver linings of this miserable year could evaporate like the midday fog. Heather Knight,, "S.F’s beloved Great Highway car closure at risk as drivers race through Sunset’s quiet streets," 17 Nov. 2020 After the fog burns off, skies should be mostly sunny with a chilly high of near 46 degrees. oregonlive, "Portland metro Monday weather: One more soggy day, sun returns Tuesday," 21 Dec. 2020 Recent Examples on the Web: Verb Early in the morning, at Reagan National Airport, where the city’s official readings are made, fog cut visibility to little more than the length of two football fields. Washington Post, "Saturday warmth outstrips even Friday’s as afternoon skies clear," 13 Dec. 2020 Nothing is as irritating as when your glasses or goggles fog up on a humid summer day or cold winter afternoon, leaving you struggling for a clear picture of your surroundings. Stack Commerce, Popular Science, "Keep your glasses, goggles, or face shield clear with this set of microfiber wipes," 14 Dec. 2020 There’s a 7-foot-high partition between each seating nook and a sheet of vinyl overhead to keep out rain — or fog dripping from two enormous street trees. John King,, "San Francisco is having a parklet moment. Here are 11 cool ones to check out right now," 27 Nov. 2020 But the feast is turning to fog as the cold weather comes and mask-wearing increases. Helen Czerski, WSJ, "Fogged-Up Glasses and Dry Fly Eyes," 12 Nov. 2020 People who cannot work safely with a mask on, such as drivers or dentists wearing glasses that could fog up, can wear a face shield. Aubrey Wieber, Anchorage Daily News, "As COVID-19 cases continue to increase, Anchorage tightens mask mandate, further limits gathering sizes," 6 Nov. 2020 Skies should clear and fog may again form overnight. oregonlive, "Portland Friday weather: Mixed day with fog, light rain, afternoon shower chances," 30 Oct. 2020 Raspberries, fireweed, fog over the river, king crabs, gulls, wild violets, salmon, and sandhill cranes all are on display here in their familiar/familial contexts. Nancy Lord, Anchorage Daily News, "New poetry book brings to readers a portrait of love, loss and transformation in Northwest Alaska," 4 Oct. 2020 The only drawback is that due to the lack of an adjustable nose wire, there was a small gap around my nose, which had a tendency to fog up my glasses. Jamie Ueda, USA TODAY, "The 10 best cloth face masks you can buy online," 2 Oct. 2020

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'fog.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

See More

First Known Use of fog


1544, in the meaning defined at sense 1a


circa 1592, in the meaning defined at transitive sense 1

History and Etymology for fog


probably back-formation from foggy

Keep scrolling for more

Learn More about fog

Statistics for fog

Last Updated

13 Jan 2021

Cite this Entry

“Fog.” Dictionary, Merriam-Webster, Accessed 22 Jan. 2021.

Keep scrolling for more

More Definitions for fog


How to pronounce fog (audio)

English Language Learners Definition of fog

 (Entry 1 of 2)

: many small drops of water floating in the air above the ground, the sea, etc.
: a state of mental confusion



English Language Learners Definition of fog (Entry 2 of 2)

: to cover or fill (something) with small drops of water : to make (something) foggy
: to become foggy
: to make (someone or something) confused


\ ˈfȯg How to pronounce fog (audio) , ˈfäg \

Kids Definition of fog

 (Entry 1 of 2)

1 : tiny drops of water floating in the air at or near the ground
2 : a confused state of mind I woke up in a fog.


fogged; fogging

Kids Definition of fog (Entry 2 of 2)

: to cover or become covered with tiny drops of water Steam from the shower fogged the mirror.
\ ˈfäg, ˈfȯg How to pronounce fog (audio) \
fogged; fogging

Medical Definition of fog

: to blur (a visual field) with lenses that prevent a sharp focus in order to relax accommodation before testing vision

Keep scrolling for more

Comments on fog

What made you want to look up fog? Please tell us where you read or heard it (including the quote, if possible).


Test Your Vocabulary

Slippery Words Quiz—Changing with the Times

  • ducreux self portrait yawning
  • What is an earlier meaning of nice?
Name That Thing

Test your visual vocabulary with our 10-question challenge!

Universal Daily Crossword

A daily challenge for crossword fanatics.

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!