Noun
air intake of a carburetor
a pneumatic horn
Source: WordNetNorway Norway has about 1,250 operational sirens (mostly Kockums air horn units rather than motorized sirens), primarily located in cities. Source: Internet
Other locales use the hi-lo signal described above, and some communities (particularly in New England and northern California) make use of coded blasts over a diaphone or air horn for fire signals, reserving the use of sirens for more serious situations. Source: Internet
“Just send a strong message: Banging pots together, using an air horn, snapping a large garbage bag.” Source: Internet
We also recommend having a portable air horn for everyone, as well as hard-soled shoes. Source: Internet