benzopyrene Syllabification: (ben·zo·py·rene)Pronunciation: /ˌbenzōˈpīrēn/Definition of benzopyrene noun Chemistry a compound that is the major carcinogen present in cigarette smoke. It also occurs in coal tar. A polycyclic aromatic hydrocarbon; chemical formula: C20H12 benzopyrene in other Oxford dictionaries Definition of benzopyrene in the British & World English dictionary