Chronos Kairos Aion

An almanac is a calendar showing the main dates of the calendar, the religious holidays, bearing ephemerides such as the phases of the moon or the duration of the days (lunar and solar calendars).

A calendar is a system for marking dates according to time. Such a system was invented by men to divide and organize time over long periods. The observation of the periodic phenomena of the environment in which they lived — such as the daily movement of the shadow, the return of the seasons or the lunar cycle — served as the first references for organizing the agricultural, social and religious life of societies.

The calendar used today in most of the world is the Gregorian calendar. In everyday language, an ephemeris designates what happens daily; the ephemeris of the day is the list of the significant events of this day.