a signal used to warn railway engine drivers in fog, consisting of a detonator placed on the line
fog signal in American English
noun
any of various types of signal used as a warning by vessels navigating in fog or mist
Word origin
[1750–60]This word is first recorded in the period 1750–60. Other words that entered Englishat around the same time include: bunker, infiltrate, permeability, railroad, swish
Examples of 'fog signal' in a sentence
fog signal
It is believed that they took a box of detonators, which are used as fog signals, from a railway depot.
Times, Sunday Times (2012)
Flames burst through the roof as about 43,000 fog signals exploded like a barrage of artillery shells going off.