• An internationally recognized distress signal, comprised of the letters S,O, and S in Morse code. This particular combination letters was not selected to mean anything; they were chosen for their simplicity of transmission. In Morse code SOS is three dots, followed by three dashes, and then three dots again. It is rarely used anymore, having been superseded by automated systems, such as those utilizing satellites.
  • acronym forsystems-on-silicon
  • acronym forsilicon-on-sapphire
  • acronym forserver operating system
  • An operating system which resides on a server.
  • An operating system which runs a server.
  • A silicon-on-insulator technique or technology in which the substrate is sapphire. Its abbreviation is SOS (2).


  • noun an international distress signal, signifying an urgent request for assistance


  • noun an international signal to show that you are in distress, in which the letters ‘s’, ‘o’, and ‘s’ are repeated in Morse code
  • noun a message broadcast to say that someone is ill and asking a relative to get in contact