<p><strong>Noun</strong></p><ul><li>Chemistry, Pharmacology: a white, bitter, slightly water-soluble alkaloid, C₂₀H₂₄N₂O₂, having needlelike crystals, obtained from cinchona bark; used in medicine chiefly in the treatment of resistant forms of malaria</li><li>a salt of this alkaloid, especially the sulfate</li></ul>