[al-kuh-loid] 
Biochemistry, Chemistry, Pharmacology| 1. | 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. |
| 2. | resembling an alkali; alkaline. |
| al·ka·loid (āl'kə-loid') n. Any of various organic compounds normally with basic chemical properties and usually containing at least one nitrogen atom in a heterocyclic ring, occurring chiefly in many vascular plants and some fungi. Many alkaloids, such as nicotine, quinine, cocaine, and morphine, are known for their poisonous or medicinal attributes. [alkal(i) + -oid.] al'ka·loi'dal (-loid'l) adj. |
alkaloid al·ka·loid (āl'kə-loid')
n.
Any of various organic compounds, such as nicotine and morphine, that have basic chemical properties and that usually contain at least one nitrogen atom in a heterocyclic ring.
kəˌlɔɪd