1. horn; alarm; whistle; foghorn
Wikipedia definition
2. Horn (acoustic)A horn is a tapered sound guide designed to provide an acoustic impedance match between a sound source and free air. This has the effect of maximizing the efficiency with which sound waves from the particular source are transferred to the air. Conversely, a horn can be used at the receiving end to optimize the transfer of sound from the air to a receiver.
Read “Horn (acoustic)” on English Wikipedia
Read “警笛” on Japanese Wikipedia
Read “Horn (acoustic)” on DBpedia


to talk about this word.