What is Fog?

Fog definition and meaning on Dictionary terms:
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, fogA.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, fogA.ging.
to become enveloped or obscured with or as if with fog.
Photography. (of a negative or positive) to become affected by fog.