calendar named for Julius Caesar and used from 45 B.C. to 1582, called the "Old Style" calendar; replaced by the Gregorian calendar.
Calendar that is used in data processing. The dates are five-digit numbers: the first two digits pertain to the year and the last three to the day of the year (001 through 365 or 366).
the calendar introduced by Julius Caesar in 46 B.C. to replace the Roman calendar. In the Julian calendar a common year is defined to comprise 365 days, and every fourth year is a leap year comprising 366 days. The Julian calendar was superseded by the Gregorian calendar.