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

Examples of caffeine in a Sentence

Her doctor told her to avoid caffeine.

Recent Examples on the Web And for some sensitive people, the amount of caffeine in chocolate can throw off sleep. — Andrea Petersen, WSJ, 12 Jan. 2022 My ability to operate on all cylinders is not possible without copious amounts of caffeine. — Chloe Melas, CNN, 3 Jan. 2022 If that’s the case, there may be nothing better than a caffeine fix. — Leada Gore | Lgore@al.com, al, 24 Dec. 2021 Everyone posted selfies of themselves, Black Rifle’s Coffee beans in one hand and a steaming mug of caffeine in the other. — Timothy Fanning, San Antonio Express-News, 22 Dec. 2021 Even dietary products like 5-Hour Energy shots have a significant ingredient overlap with multivitamins—although, presumably, your multi doesn’t also include more than 200mg of caffeine. — Amanda Mull, The Atlantic, 22 Nov. 2021 Great for people who want a light energy boost, the matcha beverage has just 45 milligrams of caffeine and is intended to help enhance your focus throughout the day. — Samantha Jones, PEOPLE.com, 19 Nov. 2021 Favorite eateries and their restorative dishes and drinks get shoutouts — along with caffeine and ibuprofen. — Autumn Thatcher, The Salt Lake Tribune, 29 Dec. 2021 Reconsider your daily caffeine intake, as the substance may help some people with migraine but trigger an attack in others. — Sara Gaynes Levy, SELF, 17 Nov. 2021

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.