Caffeine is a chemical substance found in coffee, tea, and cocoa, which affects your brain and body and makes you more active.
caffeine in British English
or 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: C8H10N4O2
See also xanthine (sense 2)
Word origin
C19: from German Kaffein, from Kaffeecoffee
caffeine in American English
(kæˈfin; ˈkæfˌin)
noun
a bitter, crystalline alkaloid, C8H10N4O2, present in coffee, tea, kola nuts, etc.: it prolongs the stimulating effects of cyclic AMP on the heart and central nervous system
: also sp. ˌcafˈfein
Word origin
Ger kaffein (now coffeïn, after ModL coffea, coffee); coined by F. F. Runge (1795-1867), Ger chemist < kaffee, coffee (< Fr café < It caffè, coffee) + -in, -ine3
Examples of 'caffeine' in a sentence
caffeine
Cut down on caffeine and avoid excess booze.
The Sun (2016)
Sugar, caffeine and alcohol can make anxiety worse.
The Sun (2016)
There are three ways of removing caffeine from the coffee bean.
Times, Sunday Times (2009)
Both alcohol and caffeine have also been linked to an increased risk of miscarriage.
The Sun (2014)
You should also avoid alcohol and caffeine.
The Sun (2014)
Cut alcohol and work on reducing your sugar and caffeine intake.
Times, Sunday Times (2014)
Too much caffeine makes me shaky and wired.
Times, Sunday Times (2006)
Consumers are more willing to do without their morning caffeine fix than to do without their medications.
Times, Sunday Times (2014)
The problem with caffeine as a stimulant is that we quickly become dependent.
Times, Sunday Times (2014)
Drinking coffee with caffeine is like pouring petrol on a fire.
Kowalski, Robert E The 8-Week Cholesterol Cure (1990)
That way you reduce your caffeine intake but avoid having withdrawal headaches.
Times, Sunday Times (2007)
Avoid foods with refined sugar and caffeine.
Times, Sunday Times (2012)
They can be brought on by stress or too much caffeine.
The Sun (2016)
And it takes as long as getting your daily caffeine fix.
Times, Sunday Times (2007)
It is best to withdraw gradually from caffeine to avoid headaches.
Colette Harris, With Theresa Cheung PCOS DIET BOOK: How you can use the nutritional approach to deal with polycysticovary syndrome (2002)
Avoid stimulants like caffeine and nicotine.
Times, Sunday Times (2009)
Resist comfort foods, too much caffeine and alcohol as they all make symptoms worse.
The Sun (2012)
Following ban, it now contains caffeine or green tea instead.
The Sun (2014)
Finish it off with a coffee - because caffeine may help those brain cells.
The Sun (2015)
There was no caffeine and no alcohol, except for the final night when the champagne came out.
Times, Sunday Times (2008)
Get an eye cream on as soon as you can: look for zingy ingredients such as caffeine, green tea and ginger.
Times, Sunday Times (2015)
In other languages
caffeine
British English: caffeine /ˈkæfiːn/ NOUN
Caffeine is a chemical substance found in coffee, tea, and cocoa, which makes you more active.