: 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
The fermentation process in kombucha creates tyramine—a compound that stimulates your nervous system—and trace amounts of caffeine.
—
Bryan Robinson, Forbes, 7 Dec. 2024
Post-pandemic, people want natural foods that can support their immune systems, clear their heads and boost their energy without caffeine jitters.
—Robert Johnson, Rolling Stone, 6 Dec. 2024
In this formulation, caffeine constricts blood vessels to reduce puffiness and dark circles, while Caudalie’s patented ingredient, Viniferine is a natural compound derived from grapevine sap and stalks, to help reduce hyperpigmentation by inhibiting melanin production.
—Conçetta Ciarlo, Vogue, 2 Dec. 2024
Many causes of tachycardia, such as consuming too much caffeine, are easy to change, while other causes can include underlying problems with your heart or other organs.
—Anna Giorgi, Verywell Health, 29 Nov. 2024
See all Example Sentences for caffeine 
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.
Bryan Robinson, Forbes, 7 Dec. 2024
Post-pandemic, people want natural foods that can support their immune systems, clear their heads and boost their energy without caffeine jitters.
—Robert Johnson, Rolling Stone, 6 Dec. 2024
In this formulation, caffeine constricts blood vessels to reduce puffiness and dark circles, while Caudalie’s patented ingredient, Viniferine is a natural compound derived from grapevine sap and stalks, to help reduce hyperpigmentation by inhibiting melanin production.
—Conçetta Ciarlo, Vogue, 2 Dec. 2024
Many causes of tachycardia, such as consuming too much caffeine, are easy to change, while other causes can include underlying problems with your heart or other organs.
—Anna Giorgi, Verywell Health, 29 Nov. 2024
See all Example Sentences for caffeine
Dictionary Entries Near caffeine
Cite this Entry
“Caffeine.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/caffeine. Accessed 22 Dec. 2024.
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
Love words? Need even more definitions?
Merriam-Webster unabridged
Share