What does foghorn mean?
A foghorn is a powerful signalling device, typically mounted on a ship, lighthouse, or coastal station, that produces a deep, resonant blast audible over long distances. Its purpose is safety: when dense fog obscures visual signals such as lights and flags, vessels sound the foghorn so that other ships and shore installations can detect their presence and position by ear. The instrument emerged in the nineteenth century, as maritime traffic grew and mechanical, steam- or compressed-air-driven horns replaced bells and cannons as warnings. In modern usage, the word also carries a vivid figurative sense, describing a person whose voice is exceptionally loud, deep, or booming — as in 'a voice like a foghorn'. This metaphor gives the term a colourful edge beyond its technical meaning. Both literal and figurative uses remain common in British and American English, making foghorn a compact example of how nautical technology enters everyday language.
A horn, especially one fitted to a ship or lighthouse, that emits a loud, low-pitched signal as a warning during fog.
"The keeper triggered the foghorn whenever the mist rolled in from the sea."
Often used with the definite article when referring to a specific installation, as in 'the foghorn at the lighthouse'.
Figuratively, an extremely loud or deep voice.
"Her laugh was a regular foghorn — you could hear it three rooms away."
Informal; usually appears in comparisons such as 'like a foghorn'.
Standard regular plural; used mainly in technical or historical contexts describing multiple installations.
"The coastguard upgraded all the foghorns along the northern coastline."
The word 'foghorn' was coined in the mid-19th century, and its booming voice became so iconic that it still stands in English for any deep, bellowing human voice.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of foghorn
Foghorn is an English compound formed simply from 'fog', a noun of uncertain ultimate origin attested in English by the sixteenth century, and 'horn', the ancient Germanic-rooted word for the wind instrument made originally from animal horn. The compound arose in the mid-nineteenth century once mechanical signalling devices were installed along coastlines. Because it is a transparent English formation rather than a borrowing, it has no cognates in other languages, though both of its components have rich independent histories.
How foghorn is actually used
Entirely neutral register; the figurative sense is informal but common in British and American English alike.
Easily confused with foghorn
Fog is the weather condition of suspended water droplets reducing visibility, while a foghorn is the loud signalling device used to warn others during that fog.