[fog, fawg]


verb (used with object), fogged, fog·ging.

verb (used without object), fogged, fog·ging.

to become enveloped or obscured with or as if with fog.
Photography. (of a negative or positive) to become affected by fog.

Origin of fog

1535–45; perhaps by back formation from foggy. See fog2
Related formsfog·less, adjectiveun·fogged, adjectiveun·fog·ging, adjective

Synonyms for fog

3. obfuscation. See cloud. 7. becloud, obfuscate, dim, blur, darken. 8. daze, befuddle, muddle, mystify.

Antonyms for fog

3. clarity. 7. clarify. 10. clear.


[fog, fawg]

noun U.S. and British Dialect.

a second growth of grass, as after mowing.
long grass left standing in fields during the winter.

Origin of fog

1300–50; Middle English fogge, fog < Scandinavian; compare Norwegian fogg long grass on damp ground, foggy Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for fog

Contemporary Examples of fog

Historical Examples of fog

  • The frolic with the child seemed to have blown away a fog from between them.

    The Spenders

    Harry Leon Wilson

  • Meantime a white film of fog spread down the bay from the northward.


    Thomas Wentworth Higginson

  • He had seen something like a heavy flash of lightning in the fog.

    The Secret Agent

    Joseph Conrad

  • Major Jelles looked meditatively at me, through his fog of smoke.

    In the Valley

    Harold Frederic

  • Then he asked me, still at the window, "What's that fog doing now?"

    Questionable Shapes

    William Dean Howells

British Dictionary definitions for fog




a mass of droplets of condensed water vapour suspended in the air, often greatly reducing visibility, corresponding to a cloud but at a lower level
a cloud of any substance in the atmosphere reducing visibility
a state of mental uncertainty or obscurity
photog a blurred or discoloured area on a developed negative, print, or transparency caused by the action of extraneous light, incorrect development, etc
a colloid or suspension consisting of liquid particles dispersed in a gas

verb fogs, fogging or fogged

to envelop or become enveloped with or as if with fog
to confuse or become confusedto fog an issue
photog to produce fog on (a negative, print, or transparency) or (of a negative, print, or transparency) to be affected by fog

Word Origin for fog

C16: perhaps back formation from foggy damp, boggy, from fog ²




  1. a second growth of grass after the first mowing
  2. grass left to grow long in winter

Word Origin for fog

C14: probably of Scandinavian origin; compare Norwegian fogg rank grass
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for fog

"thick, obscuring mist," 1540s, probably from a Scandinavian source akin to Danish fog "spray, shower, snowdrift," Old Norse fok "snow flurry," fjuk "snow storm." Cf. also Old English fuht, Dutch vocht, German Feucht "moist." Figurative phrase in a fog "at a loss what to do" first recorded c.1600.


"long grass," c.1300, probably of Scandinavian origin, cf. Norwegian fogg "long grass in a moist hollow," Icelandic fuki "rotten sea grass." The connection to fog (n.1), via a notion of long grass growing in moist dells of northern Europe, is tempting but not proven. Watkins suggests derivation from PIE *pu- "to rot, decay."


1590s, from fog (n.1). Related: Fogged; fogging.

Online Etymology Dictionary, © 2010 Douglas Harper

fog in Science



A dense layer of cloud lying close to the surface of the ground or water and reducing visibility to less than 1 km (0.62 mi). Fog occurs when the air temperature becomes identical, or nearly identical, to the dew point.
An opaque or semiopaque condensation of a substance floating in a region or forming on a surface.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

Idioms and Phrases with fog


see in a fog.

The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.