distress signal
nounUK /dɪˈstres ˈsɪɡnəl/
US /dɪˈstres ˈsɪɡnəl/
A special sign or sound that someone sends to ask for help when they are in danger.
The sailors sent a distress signal when their boat started sinking.
OTHER MEANINGS
2. A radio message sent by a ship or plane in trouble.
The coast guard picked up the distress signal from the damaged plane.
3. A flashing light or loud sound used to attract attention in an emergency.
The hikers used a mirror to flash a distress signal to the rescue team.
4. Any action or behavior that shows someone badly needs help.
Her sudden silence was a distress signal that worried her friends.