nonnuclear Syllabification: (non·nu·cle·ar)Pronunciation: /nänˈn(y)o͞oklēər/Definition of nonnuclear adjective 1not involving or relating to nuclear energy or nuclear weapons. (of a country) not possessing nuclear weapons. 2 Physics not involving, relating to, or forming part of a nucleus or nuclei. nonnuclear in other Oxford dictionaries Definition of nonnuclear in the British & World English dictionary