/,es əʊ 'es; ,ɛs o `ɛs/
n [sing]
(a) urgent message for help (sent by radio, etc, usu in code) from a ship, an aircraft, etc when in danger 紧急求救信号（船只、飞机等发出的, 通常为无线电代码）
*send an SOS to the coastguard 向海岸警卫队发出求救信号
* [attrib 作定语] an SOS message 紧急求救信号.
(b) urgent appeal for help or response (eg a radio broadcast to find relatives of a seriously ill person) 紧急求助或寻人呼叫（如为重病人寻找亲属的无线电广播）
*We heard the SOS about Bill's father on the car radio. 我们从汽车收音机里听到了有关比尔父亲的紧急寻人广播.
* (joc 谑) Our daughter sent us an SOS for some more money. 我们的女儿给我们发来了再要点钱的求救信号. Cf 参看 mayday.

n [singular]
[Date: 1900-2000; Origin: S and O, letters chosen because they were easy to send by Morse code, but often understood as short for "save our souls"]
a signal or message that a ship or plane sends when it is in danger and needs help
→mayday
an urgent message that someone is in trouble and needs help
　This is an SOS for a Mr. Tucker, whose mother is seriously ill.