GRANDDUKE Meaning of GRANDDUKE in English grandduke BrE AmE ˌɡræn d ˈdjuːk ◂ ⇨-ˈdʒuːk AmE \ -ˈduːk -ˈdjuːk ▷ grandduke|s s Longman Pronunciation English Dictionary. Английский словарь произношений Longman. 2012