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caffeine

nounattested in dialogue

  • //ˈkæfiːn//

An alkaloid, C₈H₁₀N₄O₂, found naturally in tea and coffee plants, which acts as a mild stimulant on the central nervous system.

noun

  1. 1

    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.

    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.

    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.

Etymology

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.

Forms

plural
caffeines
The neighbouring pagesAlphabetical order follows the rules of the language, not byte values: an accent decides only between two otherwise identical words, and Spanish files Ñ as a letter of its own.

Lexical content from Wiktionary, under CC BY-SA 4.0 · Source entry · Data version 2026-08-23

Rank among the words of the OpenSubtitles 2018 corpus — film and television subtitles, so spoken rather than written usage (CC BY-SA 3.0).