radiopaquePronunciation: /ˌreɪdɪəʊˈpeɪk/ (also radio-opaque)Definition of radiopaque adjective (of a substance) opaque to X-rays or similar radiation: radiopaque stones in both kidneysDerivatives radiopacityPronunciation: /-ˈpasɪti/ noun radiopaque in other Oxford dictionaries Definition of radiopaque in the US English dictionary