Vend\'emiaireVen`d['e]`miaire"\, n. [F., fr. L. vindemia vintage.] The first month of the French republican calendar, dating from September 22, 1792. Note: This calendar was substituted for the ordinary calendar, dating from the Christian era, by a decree of the National Convention in 1793. The 22d of September, 1792, which had been fixed upon as the day of the foundation of the republic, was also the date of the new calendar. In this calendar, the year, which began at midnight of the day of the autumnal equinox, was divided into twelve months of thirty days, with five additional days for festivals, and every fourth year six. Each month was divided into three decades of ten days each, the week being abolished. The names of the months in their order were, Vend['e]miaire, Brumaire, Frimaire Nivose, Pluviose, Ventose, Germinal, Flor['e]al, Prairial, Messidor, Thermidor (sometimes called Fervidor), and Fructidor. This calendar was abolished December 31, 1805, and the ordinary one restored January 1, 1806.