alkaloid

[ al-kuh-loid ]

/ ˈæl kəˌlɔɪd /

Biochemistry, Chemistry, Pharmacology

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noun

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.

adjective

resembling an alkali; alkaline.

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Origin of alkaloid

First recorded in 1825–35; alkal(i) + -oid

OTHER WORDS FROM alkaloid

non·al·ka·loid, noun, adjective

Words nearby alkaloid

alkaline soil, alkalinity, alkali rock, alkali soil, alkalize, alkaloid, alkaloidal, alkalosis, alkane, alkane series, alkanet

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

How to use alkaloid in a sentence

An alkaloid discovered by Brandes in atropa belladonna or deadly nightshade.
Cooley's Cyclopdia of Practical Receipts and Collateral Information in the Arts, Manufactures, Professions, and Trades..., Sixth Edition, Volume I|Arnold Cooley
Alkaloid, al′ka-loid, n. a vegetable principle possessing in some degree alkaline properties.
Chambers's Twentieth Century Dictionary (part 1 of 4: A-D)|Various
Apomorphia, a-po-morf′i-a, n. an alkaloid prepared from morphia by heating hydrochloric acid—a rapid and powerful emetic.
Chambers's Twentieth Century Dictionary (part 1 of 4: A-D)|Various
Alkaloid from Aconite, prepared according to process of Duquesnel.
Merck's 1899 Manual|Merck & Co.

It is the alkaloid of aconite, and generally fatal in its results.
The Red Seal|Natalie Sumner Lincoln

British Dictionary definitions for alkaloid

alkaloid

/ (ˈælkəˌlɔɪd) /

noun

any of a group of nitrogenous basic compounds found in plants, typically insoluble in water and physiologically active. Common examples are morphine, strychnine, quinine, nicotine, and caffeine

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Scientific definitions for alkaloid

alkaloid

[ ăl′kə-loid′ ]

Any of a large class of naturally occurring, complex organic compounds that contain nitrogen and have physiological effects on animals, including humans. Most alkaloids occur in plants, although some are produced by fungi and animals. Alkaloids are bases and usually form colorless crystalline solids with a bitter taste. They have a wide range of effects and are used as medicines and poisons. Morphine, quinine, strychnine, codeine, caffeine, cocaine, and nicotine are all alkaloids.