In day to day life SOS is the international code for distress "save our souls". In Medical Terminology, SOS is the abbreviation for Si-Opi-Situm. It means "If Necessary". Normally it is used by the physicians to intercommunicate amongst them regarding prescription of a particular medicine.
An SOS call is an internationally accepted Morse code distress signal. SOS is sent by people on a ship when they are in danger of drowning. This signal can be transmitted in various ways. It can be sent out as an audio tone, along a telephone wire as an electrical pulse, as long or short pulses of a radio signal, or as a visual or mechanical signal by using a flash light. It is codified as three dots, then three dashes and three dots again. This sequence is without any space between the dashes and dots. The three dots signify the letter S and the letter O is formed by three dashes.
There are various phrases that are used as a full form of SOS. They are as follows: Save Our Souls, Save Our Ship, Send Out Sailors, Save Our Sailors, Stop Other Signals and Survivors On Ship.
SOS is the commonly used description for the international Morse code distress signal. From the beginning, the SOS distress signal has actually consisted of a continuous sequence of three dots, three dashes and three dots again. They all run together without even a single letter spacing. In popular usage, SOS has become associated with phrases such as, Save Our Souls, Save Our Ship and more. But these were a later development, most likely used to help remember the correct letters. The SOS signal letters have no inherent meaning. It was simply chosen due to it being easy to remember.
Sorry Tiggersmom is wrong on this one. It is the international more code signal for distress. It was introduced in 1912. One of the first times it was used was in the Titanic disaster. Many have come up with explanations for what it means, such as "save our souls", and "save our ship". In point of fact it has no meaning It never did. It was selected for it's specific sound over the air. As a bit of super trivia, the previous distress signal was CQD.
