gastroscope Syllabification: (gas·tro·scope)Pronunciation: /ˈgastrəˌskōp/Definition of gastroscope noun an optical instrument used for inspecting the interior of the stomach. Derivatives gastroscopicPronunciation: /ˌgastrəˈskäpik/ adjective gastroscopyPronunciation: /gaˈsträskəpē/ noun gastroscope in other Oxford dictionaries Definition of gastroscope in the British & World English dictionary