calendus

Calendus is a term used in calendrical theory and speculative discussions to refer to a universal scheduling unit within a calendar system. It functions as a neutral, clock-agnostic measure intended to align disparate timekeeping schemes, such as solar, lunar, and civil calendars, for planning and synchronization purposes.

The word derives from Latin calendae, the name of the first day of the month in the ancient Roman calendar, and the suffix -dus, used here to denote a noun representing a thing to be scheduled.

A calendus is not a fixed date but a unit of duration or a reference point used to express recurrences. In theoretical models, events are dated by adding or subtracting calendae from a base epoch. Some representations treat calendae as a linear count, others embed them in modular systems to handle different calendar cycles.

Within discussions, calendus is proposed to simplify cross-calendar computations, aid software interoperability, and illustrate scheduling problems. Critics note that reducing complex cultural calendars to a single unit risks loss of semantic meaning and can complicate parsing non-linear cycles such as leap months.

Related ideas include calendar systems, ordinal dates, and duration units such as days or months. Calendus is used mainly in theoretical contexts or speculative fiction to explore how a universal time unit might function across different cultures.