superluminal Syllabification: (su·per·lu·mi·nal)Pronunciation: /ˌso͞opərˈlo͞omənl/Definition of superluminal adjective Physics denoting or having a speed greater than that of light. Origin: 1950s: from super- 'above' + Latin lumen, lumin- 'a light' + -alsuperluminal in other Oxford dictionaries Definition of superluminal in the British & World English dictionary