calendrical
Calendrical refers to anything pertaining to calendars, calendar systems, or the methods used to measure and assign dates. It is commonly used in astronomy, history, anthropology, and computer science to describe data, problems, or analyses tied to timekeeping and date conversion. Calendrical topics include the design of calendar systems, the rules for leap years, intercalation, and the determination of movable feasts such as Easter.
Historically, calendrical studies examine reforms and cultural calendars—solar, lunar, and lunisolar schemes such as the Gregorian,
In computing, calendrical calculations is a formal field focusing on date arithmetic, conversions between calendars, day-of-week
A notable reference is Calendrical Calculations, a 1997 book by Dershowitz and Reingold, which presents algorithms
The term is also used in discussions of calendrical reform, religious timekeeping, and how societies structure
Related topics include calendar, leap year, Julian day, lunar month, and astronomical cycles.