Caffeine Meaning
/ˈkæfiːn/Definition, CEFR level B2, pronunciation, examples, and quiz.
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Definition
nounAn 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.
I've been trying to cut down on caffeine.
CEFR Practice Quiz
This energy drink contains a high amount of ____, which keeps me alert.
CEFR Practice Quiz (Alternate)
Tea contains less ____ than coffee, making it a better drink at night.
Word Origin & History
Borrowed from French caféine, from café (“coffee”), or German Caffein, Kaffein (cp. Coffein, Koffein), from Kaffee (“coffee”) (cp. Kaffe, Koffee, Koffe), or Italian caffè (“coffee”) + -ine.
Literary Quotations & Historical Citations
"For example, 0.100 grams of caffeine yield by combustion, by weight, 0.180 grammes of carbonic acid."
— 1839, Justus von Liebig, translated by William Gregory, Instructions for Organic Analysis, Glasgow, Scotland, United Kingdom: Richard Griffin & Company, page 35:
"Hitherto, in consequence of its slight solubility, caffeine has been administered hypodermically only in very small doses ; in fact, at the ordinary temperature, it requires 93 parts of water to dissolve, so that a cubic centimeter would contain scarcely more than a centigram."
— 1882 October 26, C. Tanret, “Soluble Salts of Caffeine”, in American Journal of Pharmacy, volume 45, page 495:
"The US Food and Drug Administration defines this limit as anything more than 400 milligrams of caffeine daily for healthy adults. This is equivalent to four or five cups of coffee."
— 2024 March 11, Jocelyn Solis-Moreira, “Dark roasted and dangerous: Everything you should know about caffeine intoxication”, in CNN, archived from the original on 05 Apr 2024:
Explore More B2 Vocabulary Words
CEFR Practice Quiz
This energy drink contains a high amount of ____, which keeps me alert.
CEFR Practice Quiz (Alternate)
Tea contains less ____ than coffee, making it a better drink at night.