Cambridge Dictionaries online Cambridge Dictionaries online

The most popular online dictionary and thesaurus for learners of English


English definition of “booster”


noun [C] (SUPP0RTER)   /ˈbu·stər/
an action or thing that improves or increases something: Winning this game was a great morale booster for the team . A booster is also someone who is an enthusiastic supporter of something.
(Definition of booster noun (SUPP0RTER) from the Cambridge Academic Content Dictionary © Cambridge University Press)
Focus on the pronunciation of booster

More American English definitions for “booster”

Definitions of “booster” in other dictionaries

Word of the Day


a situation in which two people are friends

Word of the Day


Read our blog about how the English language behaves.

Learn More

New Words

Find words and meanings that have just started to be used in English, and let us know what you think of them.

Learn More