Klaxon
Mayday
SOS
air-raid alarm
alarm
alarm bell
alarm clock
alarm signal
alarum
alert
all clear
beacon
blinking light
burglar alarm
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
talebearer
tocsin
two-minute gun
upside-down flag
whisperer
whistle
signaling device
annunciation
annunciator
beep
beeper
doorbell
gong
intercom
keypad
klaxon