| 1. any of a class of organic compounds which contain nitrogen and have a bitter taste (Chemistry). (Chemistry) resembling an alkali; alkaline. alkaloidalka*loid (ălk&adot;*loid), alkaloidal al`ka*loidal (ăl`k&adot;*loidal), ] a. [alkali + -oid: cf. f. alcaloïde.] pertaining to, resembling, or containing, alkali.alkaloid alka*loid (ălk&adot;*loid), n. (chem.) an organic base, especially one of a class of substances occurring ready formed in the tissues of plants and the bodies of animals.note: alkaloids all contain nitrogen, carbon, and hydrogen, and many of them also contain oxygen. they include many of the active principles in plants; thus, morphine and narcotine are alkaloids found in opium |
