de Havilland, Sir Geoffrey Syllabification: (de Hav·il·land, Sir Geoffrey)Pronunciation: /də ˈhavələnd/Definition of de Havilland, Sir Geoffrey (1882–1965), English aircraft designer and manufacturer. He designed and built many aircraft, including the Mosquito used in World War II. de Havilland, Sir Geoffrey in other Oxford dictionaries Definition of de Havilland, Sir Geoffrey in the British & World English dictionary