Dictionary.com

caffeine

[ ka-feen, kaf-een, kaf-ee-in ]
/ kæˈfin, ˈkæf in, ˈkæf i ɪn /
Save This Word!

noun
Chemistry, Pharmacology. a white, crystalline, bitter alkaloid, C8H10N4O2, usually derived from coffee or tea: used in medicine chiefly as a nervous system stimulant.
Informal. a drink, usually coffee or tea, containing this stimulant:We sipped our caffeine on the balcony with its views of sea stacks, rocky coves, and the ever-changing ocean.

COMPARE MEANINGS

Click for a side-by-side comparison of meanings. Use the word comparison feature to learn the differences between similar and commonly confused words.
QUIZ
THINGAMABOB OR THINGUMMY: CAN YOU DISTINGUISH BETWEEN THE US AND UK TERMS IN THIS QUIZ?
Do you know the difference between everyday US and UK terminology? Test yourself with this quiz on words that differ across the Atlantic.
Question 1 of 7
In the UK, COTTON CANDY is more commonly known as…
Rarely caf·fein .

Origin of caffeine

First recorded in 1820–30; from French caféine, equivalent to café coffee + -ine -ine2

OTHER WORDS FROM caffeine

caf·fein·ic [ka-fee-nik, kaf-ee-in-ik], /kæˈfi nɪk, ˌkæf iˈɪn ɪk/, adjectivenon·caf·feine, nounnon·caf·fein·ic, adjective
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

How to use caffeine in a sentence

British Dictionary definitions for caffeine

caffeine

caffein

/ (ˈkæfiːn, ˈkæfɪˌiːn) /

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 2See also xanthine (def. 2)

Word Origin for caffeine

C19: from German Kaffein, from Kaffee coffee
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 caffeine

caffeine
[ kă-fēn ]

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: C8H10N4O2.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
FEEDBACK