Definitions

caffeine

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

NOUN

coffee

Synonyms

STRONGEST

cappuccino espresso

STRONG

brew decaf decoction demitasse ink java mocha mud perk

WEAK

battery acid café café au lait café noir forty weight hot stuff jamocha joe varnish remover

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

Caffeine is a stimulant that blocks adenosine receptor signaling pathways.

From Science Daily • May 30, 2026

Caffeine was also associated with a lower risk of inflammation.

From Science Daily • May 3, 2026

"Caffeine is a co-analgesic which means it can boost the effect of a painkiller," Dr Munro explains, but avoid it in the afternoon and evening as it can disrupt your sleep.

From BBC • Nov. 5, 2025

Caffeine has a time dilation on it so it could be hours that I’m in there or 30 minutes.

From Los Angeles Times • Aug. 21, 2025

A coffee bar is set off to the side, below a rustic-looking sign that says: Caffeine maintains my sunny personality.

From "The Sea in Winter" by Christine Day

caffeine

Example Sentences

Related Words