caffeine

noun

caf·feine | \ ka-ˈfēn

, ˈka-ˌfēn\

Definition of caffeine

: a bitter alkaloid C₈H₁₀N₄O₂ found especially in coffee, tea, cacao, and kola nuts and used medicinally as a stimulant and diuretic

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Examples of caffeine in a Sentence

Her doctor told her to avoid caffeine.

Recent Examples on the Web

Firming + Illuminating Mask with marine algae, SLAP IT! Retexturizing + Detoxifying Mask with caffeine, and SQUEEZE IT! Brightening + Rejuvenating Mask with citrus. — Amanda Mitchell, Marie Claire, "I Tried Butt Masks, and My Booty May Never Be The Same," 22 Feb. 2019 Talakoub recommends switching to a product with caffeine and ceramides to address inflammation and redness. — Macaela Mackenzie, Allure, "Can Using Niacinamide in Your Skin-Care Routine Cause Redness?," 22 July 2018 Followed by the Caffeine, which is an eye cream made with — yes, caffeine — to reduce puffiness and dark circles. — Angela Trakoshis, Allure, "The Inkey List Is an Under-$15 Skin-Care Brand Now at Sephora," 22 Apr. 2019 There is weaker evidence that your diet—including processed food, caffeine, and alcohol intake—as well as the use of NSAIDs may increase the permeability of the membrane, Dr. Singh says. — Sarah Jacoby, SELF, "Leaky Gut Syndrome Isn’t an Official Diagnosis, but the Symptoms Are Real," 19 Mar. 2019 Got to start the morning off with Coke, get energized and get your caffeine in. — Andrew Millan, Milwaukee Journal Sentinel, "The sweet spot? Try the locker of Brewers' Keon Broxton," 2 Mar. 2018 Some of us are quick to metabolize an after-dinner espresso; others swear off caffeine after noon. — Laura Regensdorf, Vogue, "How to Get a Better Night’s Sleep—And Why It Should Be Your Top Priority (Really)," 1 Nov. 2018 This natural beauty pick has some major de-puffing powers — the caffeine in its formula shrinks puffy morning eyes in a matter of a minute (Allure editors can attest to this). — Tanisha Pina, Allure, "13 Beauty Essentials You Should Stock Up On During Amazon Prime Day," 16 July 2018 In 2010, Four Loko nixed the caffeine from its recipe. — Sean Rossman, USA TODAY, "A sangria so potent, it reminds drinkers of Four Loko," 17 May 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'caffeine.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.