: a bitter alkaloid C8H10N4O2 found especially in coffee, tea, cacao, and kola nuts and used medicinally as a stimulant and diuretic
Examples of caffeine in a Sentence
Her doctor told her to avoid caffeine.
Recent Examples on the Web
But that warning has done little to disabuse Diet Coke lovers looking for their afternoon caffeine fix.
—
Ross Rosenfeld, Newsweek, 25 Feb. 2025
That has to do with eating, as well as caffeine and alcohol.
—Allie Volpe, Vox, 25 Feb. 2025
Sometimes, lifestyle changes can help, such as reducing alcohol or caffeine or implementing stress relief techniques.
—Vanessa Caceres, Verywell Health, 24 Feb. 2025
This social event is from 7 a.m. to 1:30 p.m. for people who like cars and caffeine.
—Jake Richardson, The Mercury News, 24 Feb. 2025
See All Example Sentences for caffeine
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Ross Rosenfeld, Newsweek, 25 Feb. 2025
That has to do with eating, as well as caffeine and alcohol.
—Allie Volpe, Vox, 25 Feb. 2025
Sometimes, lifestyle changes can help, such as reducing alcohol or caffeine or implementing stress relief techniques.
—Vanessa Caceres, Verywell Health, 24 Feb. 2025
This social event is from 7 a.m. to 1:30 p.m. for people who like cars and caffeine.
—Jake Richardson, The Mercury News, 24 Feb. 2025
See All Example Sentences for caffeine
Cite this Entry
“Caffeine.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/caffeine. Accessed 3 Mar. 2025.
Copy CitationKids Definition
caffeine
noun
caf·feine
ka-ˈfēn 
ˈka-ˌfēn
: a bitter stimulating compound found especially in coffee, tea, cacao, and kola nuts
Medical Definition
caffeine
noun
caf·feine
ka-ˈfēn, ˈka-ˌ; ˈkaf-ē-ən
: a bitter alkaloid C8H10N4O2 found especially in coffee, tea, and kola nuts and used medicinally as a stimulant and diuretic
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