caffeine

noun

caf·​feine ka-ˈfēn 

ˈka-ˌfēn

: 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

Key Ingredients: Ginseng, peptides, caffeine, squalane Best For: Skin laxity, fine lines, wrinkles, dark circles Size: 0.5 oz. —Emily Orofino, Vogue, 23 Oct. 2024

Contrary to popular belief, Pink Cocaine does not contain cocaine but is instead a combination of 2-CB, MDMA (ecstasy), ketamine, and caffeine according to the National Capital Poison Center. —Lea Veloso, StyleCaster, 22 Oct. 2024

Today, drugs already exist to help with e.g. alertness or focus (caffeine, modafinil, ritalin) but as with many other previous areas, much more is likely to be possible. —John Werner, Forbes, 14 Oct. 2024

Warrier said there are an array of factors that can lead to the condition, including excessive stress and caffeine consumption, as well as structural issues of the heart. —Sam Farmer, Los Angeles Times, 14 Oct. 2024

Word History

Etymology

German Kaffein, from Kaffee coffee, from French café

First Known Use

circa 1823, in the meaning defined above

Phrases Containing caffeine

• caffeine-free

Kids Definition

caffeine

noun

caf·​feine ka-ˈfēn 

ˈka-ˌfēn

: a bitter stimulating compound found especially in coffee, tea, cacao, and kola nuts

Medical Definition

caffeine

noun

caf·​feine ka-ˈfēn, ˈka-ˌ; ˈkaf-ē-ən 

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

caffeinic

ka-ˈfē-nik  ˌkaf-ē-ˈin-ik 

adjective