There are several synonyms for the word "fog-signal," including foghorn, siren, whistle, bell, and horn. A fog-signal is a loud warning signal used to alert ships and boats of potential hazards in times of reduced visibility, such as fog or heavy rain. A foghorn is possibly the most well-known synonym of fog-signal, emitting a loud, low-pitched sound that can be heard over great distances. A siren, on the other hand, produces a higher-pitched wailing sound that can also be used in foggy conditions. A whistle, bell, or horn can also serve as a fog-signal, depending on their power and volume. These signals can be activated manually or automatically, and their distinctive sounds are crucial for the safety of maritime traffic.