Messidor Syllabification: (Mes·si·dor)Pronunciation: /ˌmesiˈdôr/Definition of Messidor noun the tenth month of the French Republican calendar (1793–1805), originally running from June 19 to July 18. Origin:French, from Latin messis 'harvest' + Greek dōron 'gift'Messidor in other Oxford dictionaries Definition of Messidor in the British & World English dictionary