- a cloudlike mass or layer of minute water droplets or ice crystals near the surface of the earth, appreciably reducing visibility.Compare ice fog, mist, smog.
- any darkened state of the atmosphere, or the diffused substance that causes it.
- a state of mental confusion or unawareness; daze; stupor: The survivors were in a fog for days after the catastrophe.
- Photography. a hazy effect on a developed negative or positive, caused by light other than that forming the image, by improper handling during development, or by the use of excessively old film.
- Physical Chemistry. a mixture consisting of liquid particles dispersed in a gaseous medium.
verb (used with object), fogged, fog·ging.
- to cover or envelop with or as if with fog: The steam in the room fogged his glasses.
- to confuse or obscure: The debate did little else but fog the issue.
- to bewilder or perplex: to fog the mind.
- Photography. to produce fog on (a negative or positive).
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.
noun U.S. and British Dialect.
- a second growth of grass, as after mowing.
- long grass left standing in fields during the winter.
- 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
- a second growth of grass after the first mowing
- grass left to grow long in winter
“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.
- 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.
see in a fog.