air
allowed
attention
banner
beware
black
blast
caution
charge
circle
decibel
ear
emblem
emergency
equipment
forbidden
hear
horn
icon
illustration
isolated
label
law
line
loud
loudly
music
no
noise
not
outline
prohibited
quiet
restriction
round
safe
safety
shadows
ship
silence
sound
squeeze
stop
strong
symbol
thin
volume
warning
zone