archduke
noun [ C ] uk/ˌɑːtʃˈdʒuːk/ us/ˌɑːrtʃˈduːk/
大公（尤指旧时奥地利皇太子）
a man of very high rank, especially in the past in the Austrian royal family
The assassination of the Archduke Ferdinand started off the First World War. 费迪南德大公的遇刺成为第一次世界大战的导火索。