MI Printing: Word Myths: SOS Meaning

RMS Titanic April 1912

Many people believe that the Morse code group SOS has a meaning and is an acronym. SOS became associated with phrases such as "save our ship", "save our souls", "stop other signals" or "sure of sinking".

The phrases were a later development, most likely used to help teach signalmen to remember parts of the Morse Code.

As the SOS signal is a prosign, its respective letters have no inherent meaning per se, it was simply chosen due to it being easy to remember.

SOS is the commonly used description for the international Morse code distress signal ( · · · — — — · · · ). This distress signal was first adopted by the German government in radio regulations effective April 1, 1905, and became the worldwide standard under the second International Radiotelegraphic Convention, which was signed on November 3, 1906 and became effective on July 1, 1908.

RMS Titanic Radio Room

SOS remained the maritime radio distress signal until 1999, when it was replaced by the Global Maritime Distress Safety System.

In International Morse Code, three dits (shorts) form the letter S, and three dahs (longs) make the letter O, so "SOS" became an easy way to remember the correct order of the dits and dahs. In modern terminology, SOS is a Morse "procedural signal" or "prosign".

There was some resistance among the Marconi operators to the adoption of the new signal, and, as late as the April, 1912 sinking of the RMS Titanic, the ship's Marconi operators intermixed CQD (seek you or calling all stations) and SOS distress calls. However, in the interests of consistency and water safety, the use of CQD appears to have died out after this point.