caffeine or caf·fein [ ka- feen, kaf-een, kaf-ee-in ] SHOW IPA / kæˈfin, ˈkæf in, ˈkæf i ɪn / PHONETIC RESPELLING EXAMPLES | WORD ORIGIN noun . Chemistry, Pharmacology a white, crystalline, bitter alkaloid, C 8H 10N 4O 2, usually derived from coffee or tea: used in medicine chiefly as a nervous system stimulant. Origin of caffeine 1820–30;
-ine -ine 2 Related forms caf·fein·ic , [ka- fee-nik, kaf-ee- in-ik] /kæˈfi nɪk, ˌkæf iˈɪn ɪk/ adjective non·caf·feine, noun non·caf·fein·ic, adjective
Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
Examples from the Web for caffein
The symptoms were the same as those observed in cats and rabbits after the administration of
Two of the animals were seized with convulsions half an hour after the introduction of
caffein and died during the attack.
Symptoms appeared in from 10 to 15 minutes after the injection of
This compound is water-soluble, but
caffein can not be extracted from the crystals with anhydrous solvents. British Dictionary definitions for caffein noun a white crystalline bitter alkaloid responsible for the stimulant action of tea, coffee, and cocoa: a constituent of many tonics and analgesics. Formula: C 8 H 10 N 4 O 2 See also xanthine (def. 2) Word Origin for caffeine
C19: from German
Kaffein, from Kaffee coffee
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
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Word Origin and History for caffein n.
trimethyl-derivative of xanthine, 1830, from German
Kaffein, coined by chemist F.F. Runge (1795-1867), apparently from German Kaffee "coffee" (see coffee) + chemical suffix -ine (2) (German -in). The form of the English word may be via French caféine.
Online Etymology Dictionary, © 2010 Douglas Harper
Medicine definitions for caffein n. A bitter white alkaloid often derived from tea or coffee and used chiefly as a mild stimulant and in the treatment of certain kinds of headache.
The American Heritage® Stedman's Medical Dictionary
Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
Science definitions for caffein A bitter white alkaloid found in tea leaves, coffee beans, and various other plant parts. It is a mild stimulant. Caffeine is a xanthine and similar in structure to theobromine and theophylline. Chemical formula: C 8H 10N 4O 2.
The American Heritage® Science Dictionary
Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.