1. A loud horn or whistle sounded to warn ships in fog or poor visibility.
Usage: nautical; often used on lighthouses, ships, and coastal installations
2. A loud, deep voice or sound resembling a foghorn.
Usage: informal; figurative

Examples

• The foghorn blasted every few minutes to guide ships safely through the harbor.
• We could hear the foghorn from miles away during the thick fog.
• He spoke with a voice like a foghorn that could be heard across the entire room.
• The lighthouse keeper activated the foghorn when visibility dropped below safe levels.
• Her laugh was as loud as a foghorn and echoed through the hallway.
• Ships rely on the foghorn to navigate when radar and GPS are supplemented by sound signals.