Klaxon
Mayday
air-raid alarm
alarm
alarm bell
alarm clock
alarm signal
alarum
alert
all clear
beacon
blinking light
burglar alarm
buzzer
crostarie
fiery cross
fire alarm
fire bell
fire flag
five-minute gun
flashing light
fog bell
fog signal
foghorn
gale warning
hooter
horn
hue and cry
hurricane warning
lighthouse
note of alarm
occulting light
police whistle
signal of distress
siren
small-craft warning
still alarm
storm cone
storm flag
storm warning
tocsin
two-minute gun
upside-down flag
whistle
distress call
distress signal