relativistic Syllabification: (rel·a·tiv·is·tic)Pronunciation: /ˌrelətəˈvistik/Definition of relativistic adjective 1 Physics accurately described only by the theory of relativity. 2of or relating to the doctrine of relativism. Derivatives relativisticallyPronunciation: /-ik(ə)lē/ adverb relativistic in other Oxford dictionaries Definition of relativistic in the British & World English dictionary