Caffeine
/kæˈfin/
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Definition
(noun) An alkaloid, C₈H₁₀N₄O₂, found naturally in tea and coffee plants, which acts as a mild stimulant on the central nervous system.
Sentence Examples
Caffeine is a purinergic antagonist that competitively inhibits adenosine at the sites of P1 receptors.
Masha prefers coffee without caffeine.
CEFR Practice Quiz
Tea contains less ____ than coffee, making it a better drink at night.