A foghorn is a very loud horn used in foggy conditions to warn ships and boats about nearby danger, like rocky coastlines or other vessels.

Basic meaning

  • A foghorn is a warning device that makes a deep, booming sound when visibility is low because of fog.
  • It is most commonly associated with marine navigation , helping sailors know they are close to hazards when they cannot see lighthouses or the shore.

Everyday and figurative use

  • In everyday English, calling someone’s voice a “foghorn voice ” means they have a very loud, hoarse, or booming voice.
  • Dictionaries explicitly note this figurative meaning: a foghorn can also mean a loud, harsh voice , not just the device on a ship.

So if someone asks “what does foghorn mean?”, it usually refers either to the loud ship warning horn in fog, or to a person’s very loud, rough- sounding voice.

TL;DR: Foghorn = a loud warning horn used in fog at sea, and by extension, a very loud, hoarse-sounding voice.

Information gathered from public forums or data available on the internet and portrayed here.