Revolutionary calendar
noun
the calendar of the French First Republic, adopted in 1793 and abandoned in 1805, consisting of 12 months, each of 30 days, and 5 intercalary days added at the end of the year (6 every fourth year). The months, beginning at the autumnal equinox, are Vendémiaire, Brumaire, Frimaire, Nivôse, Pluviôse, Ventôse, Germinal, Floréal, Prairial, Messidor, Thermidor, and Fructidor.
British Dictionary definitions for revolutionary calendar
Revolutionary calendar
noun
the calendar adopted by the French First Republic in 1793 and abandoned in 1805. Dates were calculated from Sept 22, 1792. The months were called Vendémiaire, Brumaire, Frimaire, Nivôse, Pluviôse, Ventôse, Germinal, Floréal, Prairial, Messidor, Thermidor, and Fructidor