- A standardized international Morse code signal for distress.
Early 20th century.
Made famous for its use on the RMS Titanic (along with the earlier CQD), SOS in Morse code consists of three dots, followed by three dashes, and ending with three dots. There’s a common misconception that it’s an acronym for “Save Our Souls” or “Save Our Ship,” but more than likely it was chosen because the letters and Morse code are simple to remember and easy to transmit.
Spelling out SOS, as a visual signal, can also be used to indicate distress. It also benefits from the fact that it can be easily read both backward and upside down.
Rogers, J.G. (1985). Origins of Sea Terms. Mystic Seaport.