caffeine

noun

caf·​feine ka-ˈfēn 

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

Bye Bye Dark Spots Concealer + Serum actively treats discoloration with 2% niacinamide and helps brighten the look of dark circles, thanks to caffeine. —Angela Trakoshis, Allure, 23 Dec. 2024

Globally and in the U.S., its sales have declined as consumers look elsewhere for their caffeine buzz. —Amelia Lucas, CNBC, 20 Dec. 2024

Consuming too much caffeine could lead to symptoms like heart palpitations, high blood pressure, and anxiety. —Fran Kritz, Verywell Health, 18 Dec. 2024

Recent research reveals that caffeine has health benefits for most moderate coffee drinkers. —Erica Lamberg, Fox News, 11 Dec. 2024

Word History

Etymology

German Kaffein, from Kaffee coffee, from French café

First Known Use

circa 1823, in the meaning defined above

Phrases Containing caffeine

• caffeine-free

Kids 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

caffeinic

ka-ˈfē-nik  ˌkaf-ē-ˈin-ik 

adjective