<p><strong>Noun</strong></p><ul><li>any of a large class of organic, nitrogen-containing ring compounds of vegetable origin and sometimes synthesized, some of which are liquid but most of which are solid, that have a bitter taste, that are usually water-insoluble and alcohol-soluble, that combine with acids without the loss of a water molecule to form water-soluble hydrochlorides, hydrobromides, or the like, and that usually exhibit pharmacological action, as nicotine, morphine, or quinine.</li><li>(not in technical use) an alkali metal.</li><li>obsolete: any of various other compounds, as the carbonates of sodium and potassium.</li><li>Agriculture: a soluble mineral salt or a mixture of soluble salts, present in some soils, especially in arid regions, and detrimental to the growing of most crops.</li></ul><p><strong>End of Response</strong></p>