Trajan Syllabification: (Tra·jan)Pronunciation: /ˈtrājən/Definition of Trajan (circa 53-117), Roman emperor 98-117; Latin name Marcus Ulpius Traianus. His reign is noted for the Dacian wars (101–106), which ended in the annexation of Dacia as a province. Trajan in other Oxford dictionaries Definition of Trajan in the British & World English dictionary