The month was named after the Occitan word vendemiaire 'grape harvester'.
Vendémiaire was the first month of the autumn quarter (mois d'automne).
Like all FRC months Vendémiaire lasted 30 days and was divided into three 10-day weeks, called décades (decades).
In accordance with the suggestion of Fabre d'Églantine, each of the days of the republican year was consecrated to some useful object.
[1] Thus every day in Vendémiaire had the name of an agricultural or ornamental plant, except the 5th (Quintidi) and 10th day (Decadi) of every decade, which had the name of a domestic animal (Quintidi) or an agricultural tool (Decadi).