Definition of caffeine
: 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.
Origin and Etymology of caffeine
German Kaffein, from Kaffee coffee, from French café
First Known Use: circa 1823
CAFFEINE Defined for English Language Learners
Definition of caffeine for English Language Learners
: a substance that is found especially in coffee and tea and that makes you feel more awake
CAFFEINE Defined for Kids
Definition of caffeine for Students
: a substance found especially in coffee and tea that makes a person feel more awake
Seen and Heard
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