Klaxon (noun)

A loud horn used as a warning signal, especially on automobiles and boats.

Origin:

The term "klaxon" originated in the early 20th century, it is a brand name of a type of loud horn used as a warning signal, especially on automobiles and boats.

Examples:

1. The klaxon of the ambulance made him jump as it rushed past him.
2. The boat's klaxon signaled that it was about to depart.
3. He honked the klaxon to warn the pedestrians that he was turning.
4. The loud klaxon startled everyone in the room.
5. They heard the klaxon of the fire truck in the distance.