If someone in a plane or ship sends out a Mayday or a Mayday message, they send out a radio message calling for help because they are in serious difficulty.
He raced to pick up the lifejackets while his stepmother sent out a Mayday call.
2. convention
'Mayday! Mayday!' is the phrase that is used in Mayday messages to indicate that help is needed.
Mayday in British English
(ˈmeɪˌdeɪ)
noun
the international radiotelephone distress signal
Word origin
C20: phonetic spelling of French m'aidez help me
Mayday in American English
(ˈmeɪˌdeɪ)
noun
the international radiotelephone signal for help, used by ships and aircraft in distress
Word origin
prob. short for Fr (venez) m'aider, (come) help me
Examples of 'Mayday' in a sentence
Mayday
He disappeared inside the helicopter and my first thought was he'd gone to radio a Mayday message.
Brierley, David SKORPION'S DEATH
It was the forerunner to the sos call which in turn was superseded, in the days of voice radio, by the now standard Mayday call.
Lunnon-Wood, Mike LET NOT THE DEEP
`Surely the Nova Scotia had radio and got off a Mayday signal!
Jenkins, Geoffrey A DAYSTAR OF FEAR
Only person that counted was the one at the controls, the guy who could grab the radio, make the Mayday call.