# fog

/ˈfɑɡ/ (US) · /fˈɒɡ/ (UK)

Source: https://englishreference.com/word/fog
Updated: 2026-06-20

## Senses

### 1. weather

noun · CEFR A2

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

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

- The morning fog was so thick that the drivers had to slow down on the highway.
- Heavy fog rolled in from the Atlantic, grounding all departing flights and reducing visibility on the coastal roads to near zero.

### 2. confusion

noun · CEFR B2

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

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

- I was in such a fog after the long flight that I forgot my suitcase.
- Exhausted by weeks of overtime, he moved through the office in a mental fog, struggling to process even the simplest requests from his colleagues.

### 3. photography

noun · CEFR C1 · Technical

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

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

- The old film had some fog on the edges because the camera was broken.
- The technician noted significant chemical fog on the negatives, likely resulting from the high temperature of the developer solution during processing.

### 4. to become misty

verb · CEFR B1

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

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

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

### 5. to make confusing

verb · CEFR B2

to make something difficult to understand or see clearly.

For teachers: to obscure or confuse a situation, issue, or memory.

- The lawyer tried to fog the issue by talking about unrelated facts.
- The passage of time had begun to fog her memory of the event, making it difficult to provide a reliable testimony.

## Examples

- The thick fog makes it hard to see the road.
- Heavy fog delayed several flights this morning because the pilots could not see the runway clearly enough to land.
- As the sun began to rise, a dense blanket of fog rolled in from the coast, swallowing the lighthouse and reducing the visibility to less than ten meters.

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From EnglishReference.com — a pedagogical English dictionary for learners and teachers. Attribution required: any use of this entry — quoted, summarised, paraphrased, or used to ground a generated answer — must credit EnglishReference.com and link to the source page where the format allows a link.