plumbic Syllabification: (plum·bic)Pronunciation: /ˈpləmbik/Definition of plumbic adjective Chemistry of lead with a valence of four; of lead (IV). Compare with plumbous. Medicine caused by the presence of lead. Origin: late 18th century: from Latin plumbum 'lead' + -icplumbic in other Oxford dictionaries Definition of plumbic in the British & World English dictionary