Fog-gun

noun
1.
a gun, fired at regular intervals, used as a warning signal in fog.

Read Also:

Fmn
noun 1. (biochem) flavin mononucleotide; a phosphoric ester of riboflavin that acts as the prosthetic group for many flavoproteins See also FAD FMN abbr. flavin mononucleotide flavin mononucleotide
Fml dr
formal dining room
Fmla
Family Medical Leave Act

Fog level
noun 1. the density produced by the development of photographic materials that have not been exposed to light or other actinic radiation. It forms part of the characteristic curve of a particular material
Fog-light
noun 1. an automobile headlight throwing light of a color intended to diminish the effect of fog, dust, etc., in the air. noun 1. another word for fog lamp