Where it sits
Its real origin is a documented choice of signal; the phrases are memory aids added afterwards.
What it doesn't mean
It doesn't stand for anything. Etymonline: the letters were 'chosen arbitrarily as being easy to transmit and difficult to mistake'. 'Save our souls' is a backronym attached later.
Same answer. Wikipedia notes that when it was first agreed in 1906, SOS was merely a distinctive Morse sequence, initially not an abbreviation.
Formally, it's sent as one unbroken sequence — three dots, three dashes, three dots — with no gaps between the 'letters'. Reading it as S-O-S is just a way to remember it.
What it really means
Almost everyone knows what SOS stands for: Save Our Souls. Or perhaps Save Our Ship. The two answers can't both be right, and in fact neither is. SOS doesn't stand for anything.
Why it's wrong. SOS was chosen for its sound, not its letters. In Morse code it's three dots, three dashes, three dots, sent as a single unbroken pattern. Etymonline says the letters were chosen arbitrarily as being easy to transmit and difficult to mistake, and states plainly that it is not an initialism for "save our ship" or anything else. Wikipedia makes the same point: when it was first agreed internationally in 1906, SOS was simply a distinctive Morse sequence. The phrases came afterwards, as backronyms.
Technically it isn't even three letters. Formally, the signal is sent with no gaps between the "S", "O" and "S". Reading it as letters is just the easiest way to remember the pattern.
What's actually known. SOS appears in German government maritime radio regulations from 1 April 1905. The first International Radiotelegraph Convention, signed on 3 November 1906, adopted it, and it became the worldwide standard on 1 July 1908. It had a rival: CQD, used by Marconi operators, from CQ, the call to all stations, plus D for danger. Old habits lingered. When Titanic sank in April 1912, its operators sent both.
By 1918, SOS was also being used figuratively for any urgent appeal. Its spoken counterpart, mayday, was agreed in 1923. For more than a century the signal has done its job without ever needing to stand for a word.
Where it comes from
- 1 April 1905
SOS appears in German government maritime radio regulations (Wikipedia).
- 3 November 1906
The first International Radiotelegraph Convention, signed in Berlin, includes it in its service regulations (Wikipedia).
- 1 July 1908
The convention comes into effect, making SOS a worldwide standard (Wikipedia).
- April 1912
Titanic's radio operators mix CQD and SOS calls; CQD appears to die out after this (Wikipedia).
- By 1918
SOS is used figuratively for any urgent appeal for help (Etymonline).
In real life
- The hikers spelled SOS in stones on the hillside, and a helicopter crew spotted it the next morning.
- Her text was a one-word SOS: 'help' — the printer had jammed an hour before the deadline.
- The signal is sent as one continuous pattern, dot-dot-dot dash-dash-dash dot-dot-dot, with no gaps.
Questions
Q01What does SOS stand for?
Nothing. It's a Morse code signal chosen for its pattern — three dots, three dashes, three dots — which is easy to send and difficult to mistake. 'Save Our Souls' and 'Save Our Ship' were attached to it later as memory aids.
Q02When did SOS become the distress signal?
It appeared in German radio regulations in April 1905, was adopted by the first International Radiotelegraph Convention in November 1906, and became the worldwide standard when that came into force on 1 July 1908.
Q03What was used before SOS?
Marconi operators used CQD — CQ, the general call to all stations, plus D for danger, according to Etymonline. As late as the Titanic in 1912, operators used both CQD and SOS.
Q04What's the spoken version of SOS?
Mayday, which Etymonline says was agreed in early 1923 as the international radio-telephone distress call.
Sources
- SOS — Online Etymology Dictionary.
- SOS — Wikipedia (history of the signal).
- International Radiotelegraph Convention (1906) — Wikipedia.