!MAY May is the fifth month of the year in Gregorian calendar. It has 31 days. Opinion as to how it derived its name is divided. Many believe that the month is so called from a Sanskrit word signifying to grow, as being the shooting or growing month. However, there are several others who believe that the month derives its name from the Latin word Maius, which is believed to have come from Maia, the mother of the god Hermes.