julian
adj.adj. relating to the calendar introduced by Julius Caesar. It was used in the West for centuries before the modern Gregorian calendar replaced it.
adj. pertaining to the solar calendar introduced by Julius Caesar in 46 BC. Often used in historical or astronomical contexts to distinguish dates from those in the modern Gregorian system.
The Julian calendar has a leap year every four years.
Historians must often convert Julian dates to Gregorian ones when studying documents from the sixteenth century.
While the Gregorian reform corrected the drift of the solar year, some Orthodox churches still observe religious holidays according to the Julian reckoning, resulting in different celebration dates.
Typically capitalised as it derives from a proper name. Usually precedes the noun it modifies, such as 'calendar', 'year', or 'date'.