fog

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A new growth of grass appearing on a field that has been mowed or grazed.
• noun Tall, decaying grass left standing after the cutting or grazing season.
• noun Condensed water vapor in cloudlike masses lying close to the ground and limiting visibility.
• noun An obscuring haze, as of atmospheric dust or smoke.
• noun A mist or film clouding a surface, as of a window, lens, or mirror.
• noun A cloud of vaporized liquid, especially a chemical spray used in fighting fires.
• noun A state of mental vagueness or bewilderment.
• noun Something that obscures or conceals; a haze.
• noun A blur on a developed photographic image.
• intransitive verb To cover or envelop with fog.
• intransitive verb To cause to be obscured; cloud.
• intransitive verb To make vague, hazy, or confused.
• intransitive verb To obscure or dim (a photographic image).
• intransitive verb To be covered with fog.
• intransitive verb To be blurred, clouded, or obscured.
• intransitive verb To be dimmed or obscured. Used of a photographic image.

from The Century Dictionary.

• noun Aftergrass; a second growth of grass; aftermath; also, long grass that remains on land through the winter; foggage.
• noun Moss.
• To envelop with or as with fog; shroud in mist or gloom; obscure; befog.
• To cloud or coat with a uniform coating or discoloration, as in photography: as, an over-alkaline developer will fog the plate. see fog, n., 3.
• To become covered or filled with fog.
• In photography, to become clouded or coated with a uniform coating or discoloration: said of a negative in course of development. See fog, n., 3.
• To seek gain by base or servile practices (whence pettifogger).
• Gross; fat; clumsy.
• To feed off the fog or pasture in winter: as, to fog cattle.
• To eat off the fog from: as, to fog a field.
• To become covered with fog or moss.
• noun An atmospheric haze due to the presence of fine solid matter, such as dust or fine soot from soft coal fires or ashes from forest and prairie fires. These carbon particles collect about themselves special atmospheres of aqueous vapor and other gases. The spectrum of the transmitted light shows only the red and ultra-red waves. As the upper layers of the dry fog cool off by radiation and the little atmospheres of vapor become water, the dry fog changes to a drizzling mist and often to steady rain. Prairie fires and the resultant dry fog are mentioned by Marco Polo in his travels in India.
• noun The aggregation of a vast number of minute globules of water in the air near the earth's surface, usually produced by the cooling of the air below the dew-point, whereby a portion of its vapor is condensed.
• noun Hence A state of mental obscurity or confusion: as, to be in a fog of doubt.
• noun In photography, a uniform coating covering a developed plate, more or less destructive to the picture in proportion to its opacity. It results from chemical impurities, from exposure of the sensitized film to light, from errors in manipulation, etc.

from the GNU version of the Collaborative International Dictionary of English.

• noun Prov.Eng., Prov.Eng. A second growth of grass; aftergrass.
• noun Prov.Eng. Dead or decaying grass remaining on land through the winter; -- called also foggage.
• noun Watery vapor condensed in the lower part of the atmosphere and disturbing its transparency. It differs from cloud only in being near the ground, and from mist in not approaching so nearly to fine rain. See cloud.
• noun A state of mental confusion.
• noun (Photog.) Cloudiness or partial opacity of those parts of a developed film or a photograph which should be clear.
• noun a bell, horn, whistle or other contrivance that sounds an alarm, often automatically, near places of danger where visible signals would be hidden in thick weather.
• noun a mass of fog resting upon the sea, and resembling distant land.
• noun a bank of fog arranged in a circular form, -- often seen on the coast of Newfoundland.
• transitive verb To envelop, as with fog; to befog; to overcast; to darken; to obscure.
• transitive verb (Photog.) To render semiopaque or cloudy, as a negative film, by exposure to stray light, too long an exposure to the developer, etc.
• intransitive verb (Photog.) To show indistinctly or become indistinct, as the picture on a negative sometimes does in the process of development.
• transitive verb (Agric.) To pasture cattle on the fog, or aftergrass, of; to eat off the fog from.
• intransitive verb obsolete To practice in a small or mean way; to pettifog.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun uncountable A thick cloud that forms near the ground; the obscurity of such a cloud.
• noun uncountable A mist or film clouding a surface.