Severus, Septimius Syllabification: (Se·ve·rus, Septimius)Pronunciation: /səˈvi(ə)rəs/Definition of Severus, Septimius (146–211), Roman emperor 193–211; full name Lucius Septimius Severus Pertinax. In 208, he led an army to Britain to suppress a rebellion in the north and later died at York. Severus, Septimius in other Oxford dictionaries Definition of Severus, Septimius in the British & World English dictionary