Macbeth Syllabification: (Mac·beth)Pronunciation: /məkˈbeTH, ˌmak-/Definition of Macbeth (circa 1005–57), king of Scotland 1040–57. He came to the throne after killing his cousin Duncan I in battle and was himself defeated and killed by Malcolm III. Macbeth in other Oxford dictionaries Definition of Macbeth in the British & World English dictionary