Lassus, Orlande de Syllabification: (Las·sus, Orlande de)Pronunciation: /ˈläsəs/Definition of Lassus, Orlande de (circa 1532–94), Flemish composer; Italian name Orlando di Lasso. He wrote over 2,000 secular and sacred works. Lassus, Orlande de in other Oxford dictionaries Definition of Lassus, Orlande de in the British & World English dictionary