fog (noun)

droplets of water vapor suspended in the air near the ground

fog, fogginess, murk, murkiness (noun)

an atmosphere in which visibility is reduced because of a cloud of some substance

daze, fog, haze (verb)

confusion characterized by lack of clarity

obscure, befog, becloud, obnubilate, haze over, fog, cloud, mist (verb)

make less visible or unclear

"The stars are obscured by the clouds"; "the big elm tree obscures our view of the valley"

Fog

Fog is a collection of liquid water droplets or ice crystals suspended in the air at or near the Earth's surface. While fog is a type of stratus cloud, the term "fog" is typically distinguished from the more generic term "cloud" in that fog is low-lying, and the moisture in the fog is often generated locally. Fog is distinguished from mist only by its density, as expressed in the resulting decrease in visibility: Fog reduces visibility to less than 1 km, whereas mist reduces visibility to no less than 1 km. For aviation purposes in the UK, a visibility of less than 5 km but greater than 999 m is considered to be mist if the relative humidity is 70% or greater – below 70% haze is reported. The foggiest place in the world is the Grand Banks off the island of Newfoundland, the meeting place of the cold Labrador Current from the north and the much warmer Gulf Stream from the south. Some of the foggiest land areas in the world include Argentia, Newfoundland and Point Reyes, California, each with over 200 foggy days per year. Even in generally warmer southern Europe, thick fog and localized fog is often found in lowlands and valleys, such as the lower part of the Po Valley and the Arno and Tiber valleys in Italy or Ebro Valley in northeastern Spain, as well as on the Swiss plateau, especially in the Seeland area, in late autumn and winter. Other notably foggy areas include Hamilton, New Zealand, coastal Chile, coastal Namibia, and the Severnaya Zemlya islands.

Fog

Fog is a visible aerosol consisting of tiny water droplets or ice crystals suspended in the air at or near the Earth's surface. Fog can be considered a type of low-lying cloud usually resembling stratus, and is heavily influenced by nearby bodies of water, topography, and wind conditions. In turn, fog affects many human activities, such as shipping, travel, and warfare. Fog appears when water vapor (water in its gaseous form) condenses. During condensation, molecules of water vapor combine to make tiny liquid water droplets that hang in the air. Sea fog, which shows up near bodies of saline water, is formed as water vapor condenses on bits of salt. Fog is similar to, but less transparent than, mist.