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REFERENCE

fog

n. · v.
US //ˈfɑɡ// UK //fˈɒɡ// fog
  1. 1 weather (n.)
    A2 Elementary

    a thick cloud of very small drops of water in the air that is close to the ground and makes it difficult to see.

    a dense meteorological aerosol of water droplets or ice crystals near the ground, reducing horizontal visibility to less than one kilometre.

    Example

    The morning fog was so thick that the drivers had to slow down on the highway.

    Example

    Heavy fog rolled in from the Atlantic, grounding all departing flights and reducing visibility on the coastal roads to near zero.
  2. 2 confusion (n.)
    B2 Upper Intermediate

    a state of mind where you feel confused and cannot think clearly.

    a state of mental obscurity or confusion, often characterised by a lack of focus or slow cognitive processing.

    Example

    I was in such a fog after the long flight that I forgot my suitcase.

    Example

    Exhausted by weeks of overtime, he moved through the office in a mental fog, struggling to process even the simplest requests from his colleagues.
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  1. 3 photography (n.)
    C1 Advanced Technical Photography

    a blur or dark area on a photograph caused by light leaking in or chemical errors.

    a silver deposit or general darkening on a photographic negative or print, typically caused by stray light or chemical over-development.

    Example

    The old film had some fog on the edges because the camera was broken.

    Example

    The technician noted significant chemical fog on the negatives, likely resulting from the high temperature of the developer solution during processing.
  2. 4 to become misty (v.)
    B1 Intermediate

    to become covered with small drops of water so that you cannot see through it.

    to become obscured by condensation or moisture, typically on a glass surface.

    Example

    The bathroom mirror started to fog up while I was taking a hot shower.

    Example

    The pilot watched the cockpit windows begin to fog as the aircraft descended rapidly into the humid tropical air mass.

    Usage

    often used with 'up'
    • mist up
    • steam up
  3. 5 to make confusing (v.)
    B2 Upper Intermediate

    to make something difficult to understand or see clearly.

    to obscure or confuse a situation, issue, or memory.

    Example

    The lawyer tried to fog the issue by talking about unrelated facts.

    Example

    The passage of time had begun to fog her memory of the event, making it difficult to provide a reliable testimony.
Etymology 1

Origin uncertain; but probably of North Germanic origin. Probably either a back-formation from foggy (“covered with tall grass; thick, marshy”), from the earlier-attested fog (“tall grass”) (see below), or from or related to Danish fog (“spray, shower, drift, storm”), related to Icelandic fok (“spray, any light thing tossed by the wind, snowdrift”), Icelandic fjúka (“to blow, drive”), from Proto-Germanic feukaną (“to whisk, blow”), from Proto-Indo-European pug- (“billow, bulge, drift”), from pew-, pow- (“to blow, drift, billow”), in which case related to German fauchen (“to hiss, spit, spray”).

Etymology 2

From Middle English fogge (“tall grass”), probably from Norwegian fogg (“tall, worthless grass”); compare Scots fog (“moss; lichen”).

Etymology 3

Compare Old Dutch focker.

Word family
Idioms1 entry

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