caffeine

noun

caf·​feine ka-ˈfēn How to pronounce caffeine (audio)
ˈka-ˌfēn
: 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
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
These thoughtful beverages, which supplement coffee with mushrooms like reishi, lion’s mane, and chaga, offer a lower dose of caffeine alongside a higher amount of micronutrients. Deanna Pai, Vogue, 23 Mar. 2025 Instant coffee may be a great choice for folks looking to moderate their caffeine intake or sensitive to caffeine. Alexandra Emanuelli, Southern Living, 23 Mar. 2025 Fernandez-Mendoza: Good sleep hygiene habits include cutting down on caffeine and alcohol, quitting smoking and exercising regularly. Julio Fernandez-Mendoza, The Conversation, 20 Mar. 2025 Perhaps your perfect caffeine buzz comes from a cup of something sweet and creamy, paired with a decadent pasty in a pink-walled cafe. Jenny Berg, Allure, 19 Mar. 2025 See All Example Sentences for caffeine

Word History

Etymology

German Kaffein, from Kaffee coffee, from French café

First Known Use

circa 1823, in the meaning defined above

Time Traveler
The first known use of caffeine was circa 1823

Browse Nearby Words

Cite this Entry

“Caffeine.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/caffeine. Accessed 31 Mar. 2025.

Kids Definition

caffeine

noun
caf·​feine ka-ˈfēn How to pronounce caffeine (audio)
ˈka-ˌfēn
: a bitter stimulating compound found especially in coffee, tea, cacao, and kola nuts

Medical Definition

caffeine

noun
: a bitter alkaloid C8H10N4O2 found especially in coffee, tea, and kola nuts and used medicinally as a stimulant and diuretic
caffeinic adjective

More from Merriam-Webster on caffeine

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