May Day occurs on May 1 and refers to several public holidays. In many countries, May Day is synonymous with International Workers’ Day, or Labour Day, which celebrates the social and economic achievements of the labour movement. As a day of celebration the holiday has ancient origins, and it can relate to many customs that have survived into modern times.
Mayday is an emergency code word used internationally as a distress signal in voice procedure radio communications. It derives from the French venez m’aider, meaning ‘come help me’. It is used to signal a life-threatening emergency by many groups, such as police forces, pilots, firefighters, and transportation organizations. The call is always given three times in a row (Mayday Mayday Mayday) to prevent mistaking it for some similar-sounding phrase under noisy conditions.