meconidineChem.|miːˈkɒnɪdɪn| Also -in. [f.Gr. µήκων poppy + -id- + -ine5: cf.quinidine.] An amorphous alkaloid found in opium; discovered by Hesse in 1870. 1871Watts tr.Gmelin's Handbk.Chem. XVIII. 199 Meconidine... Contained in the aqueous extract of opium.