Saint-Simon, Duc de Syllabification: (Saint-Si·mon, Duc de)Pronunciation: /ˌsaN sēˈmôN/Definition of Saint-Simon, Duc de (1675–1755), French writer; born Louis de Rouvroy. He is best known for his Mémoires, a detailed record of court life between 1694 and 1723 during the reigns of Louis XIV and XV. Saint-Simon, Duc de in other Oxford dictionaries Definition of Saint-Simon, Duc de in the British & World English dictionary