1An international code signal of extreme distress, used especially by ships at sea.
- ‘they put out an SOS that they were on fire’
- 1.1An urgent appeal for help.
- ‘I'd thought of phoning a desperate SOS to James’
- 1.2British A message broadcast in an emergency in an attempt to contact a person whose whereabouts are not known.
- ‘here is an SOS message for Mr Arthur Brown about his brother, who is dangerously ill’
Early 20th century letters chosen as being easily transmitted and recognized in Morse code; by folk etymology an abbreviation of save our souls.
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