caffeine /ˈkæfiːn/noun 1forms 1phrases 1 noun1 •An alkaloid, C₈H₁₀N₄O₂, found naturally in tea and coffee plants, which acts as a mild stimulant on the central nervous system.For example, 0.100 grams of caffeine yield by combustion, by weight, 0.180 grammes of carbonic acid. — 1839 formscaffeines Phrases with caffeine caffeine upTo ingest caffeine, such as by drinking coffee or tea.
