caffeine

play
noun caf·feine \ ka-ˈfēn , ˈka-ˌ \

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

  1. Her doctor told her to avoid caffeine.

Recent Examples of caffeine from the Web

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'caffeine.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

Origin and Etymology of caffeine

German Kaffein, from Kaffee coffee, from French café

Other Biochemistry Terms


CAFFEINE Defined for English Language Learners

caffeine

play
noun

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

caffeine

play
noun caf·feine \ ka-ˈfēn , ˈka-ˌfēn \

Definition of caffeine for Students

:a substance found especially in coffee and tea that makes a person feel more awake

Medical Dictionary

caffeine

play
noun caf·feine \ ka-ˈfēn, ˈka-ˌ; ˈkaf-ē-ən \

medical Definition of caffeine

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

caffeinic

play \ka-ˈfē-nik, ˌkaf-ē-ˈin-ik\ adjective


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