caffeine

American  

[ka-feen, kaf-een, kaf-ee-in] / kæˈfin, ˈkæf in, ˈkæf i ɪn /

Rarely caffein

noun

1. Chemistry, Pharmacology. a white, crystalline, bitter alkaloid, C 8 H 10 N 4 O 2 , usually derived from coffee or tea: used in medicine chiefly as a nervous system stimulant.

2. Informal. a drink, usually coffee or tea, containing this stimulant.

   We sipped our caffeine on the balcony with its views of sea stacks, rocky coves, and the ever-changing ocean.

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caffeine British  

/ ˈkæfiːn, ˈkæfɪˌiːn /

noun

1. a white crystalline bitter alkaloid responsible for the stimulant action of tea, coffee, and cocoa: a constituent of many tonics and analgesics. Formula: C 8 H 10 N 4 O 2 See also xanthine

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caffeine Scientific  

/ kă-fēn′ /

1. A bitter white alkaloid found in tea leaves, coffee beans, and various other plant parts. It is a mild stimulant. Caffeine is a xanthine and similar in structure to theobromine and theophylline. Chemical formula: C ₈ H ₁₀ N ₄ O ₂ .

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Other Word Forms

• caffeinic adjective
• noncaffeine noun
• noncaffeinic adjective

Etymology

Origin of caffeine

First recorded in 1820–30; from French caféine, equivalent to café coffee + -ine -ine ²

Compare meaning

How does caffeine compare to similar and commonly confused words? Explore the most common comparisons:

• theobromine vs. caffeine

Example Sentences

Scientists found that consuming caffeine at night can increase impulsive behavior, raising the likelihood of risky or uncontrolled actions.

From Science Daily

Yaupon holly was the only plant indigenous to this land that contained caffeine.

From Literature

Kirkland Signature energy drinks mimic Celsius’s look, flavors, and 200 milligrams of caffeine, causing Celsius shares to fall.

From The Wall Street Journal

Even so, nectar contains other compounds, such as nicotine and caffeine, that are known to influence animal behavior.

From Science Daily

It was a group powered by caffeine, Johnston said, and their coffee came in handy when they needed a liquid prop to do quick demos with the prototypes to test their absorbency.

From The Wall Street Journal

Related Words

• cappuccino
• espresso