caffeine
noun
caf·feine
| \ ka-ˈfēn
, ˈka-ˌfēn\
, 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
Avoid beverages with caffeine, alcohol or large amounts of sugar because these can result in the loss of body fluid. — Jasper Scherer, Houston Chronicle, "Heat advisory in effect Saturday in Houston, surrounding area," 17 Aug. 2019 Blends are also frequently spiked with extra caffeine, sugars, steroids, or other ingredients that haven’t been tested at all. — Sara Harrison, WIRED, "The Wild, Unregulated World of Sports Supplements," 22 July 2019 What are those things that harm your body: sugar, white flour, meat and dairy, and caffeine (and non-food). — The Rev. Ellin Dize, baltimoresun.com/maryland/carroll, "Dize: Eat food that nourishes all your organs and will do no harm," 12 July 2019 The manufacturers, however, claimed the caffeine was a flavor enhancer. — Sara Talpos, Quartz, "The dangers of energy drinks can be fatal—especially for teens," 10 July 2019 The eye cream contains a blend of caffeine, green tea extract, probiotics, and pomegranate extract. — Meagan Fredette, Teen Vogue, "Does KylieSkin Care Live Up To The Hype?," 22 May 2019 The same effect as putting caffeine in the municipal drinking water. — Peter Hartlaub, SFChronicle.com, "Renel Brooks-Moon was born for this; SF Giants announcer has her father’s voice," 19 Aug. 2019 Tuello handed her a cup of coffee, just one human in a free, caffeine-permitting country to another, and the ordinariness of it—the banality, maybe—felt somehow obscene. — Sophie Gilbert, The Atlantic, "When Women Are Accused of Complicity," 17 Aug. 2019 Need a caffeine boost before that 7 a.m. class or a place to pull your first all-nighter? — Danielle Woodward, azcentral, "Everything you need to know about going to college in metro Phoenix. Seriously, everything," 17 Aug. 2019These 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.
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More Definitions for caffeine
caffeine
noun
English Language Learners Definition of caffeine
: a substance that is found especially in coffee and tea and that makes you feel more awake
See the full definition for caffeine in the English Language Learners Dictionary
caffeine
noun
caf·feine
| \ ka-ˈfēn
, ˈka-ˌfēn\
, ˈka-ˌfēn\
Kids Definition of caffeine
: a substance found especially in coffee and tea that makes a person feel more awake
caffeine
noun
caf·feine
| \ ka-ˈfēn, ˈka-ˌ; ˈkaf-ē-ən
\
\
Medical Definition of caffeine
: a bitter alkaloid C8H10N4O2 found especially in coffee, tea, and kola nuts and used medicinally as a stimulant and diuretic
Other Words from caffeine
caffeinic
\ ka-ˈfē-nik
, ˌkaf-ē-ˈin-ik
\
adjective
, ˌkaf-ē-ˈin-ik
\
adjective
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