The era name is the name a calendar uses to refer to a period of time reckoned from a fixed point or event. For example, "A.D." or "C.E." is the current era in the Gregorian calendar.
The valid values for era are listed in the Eras property of the appropriate class derived from Calendar. For example: JapaneseCalendar.Eras displays a list of eras that are supported by this implementation.