ThermidorPronunciation: /ˈθəːmɪdɔː, tɛʀmidɔʀ/Definition of Thermidor noun the eleventh month of the French Republican calendar (1793–1805), originally running from 19 July to 17 August. Derivatives Thermidorian adjective Origin:French, from Greek thermē 'heat' + dōron 'gift'Thermidor in other Oxford dictionaries Definition of Thermidor in the US English dictionary