Definition of republican calendar in English:

republican calendar

noun

historical
  • A reformed calendar officially introduced by the French Republican government on 5 October 1793.

    The republican calendar had twelve months of thirty days each, with five days of festivals at the year's end (six in leap years). It was abandoned under the Napoleonic regime and the Gregorian calendar was formally reinstated on 1 January 1806.

Origin

Late 18th century; earliest use found in Almanach pour l'An IIe de la Republique Francaise. After French calendrier républicain.