booster

noun

boost·​er ˈbü-stər How to pronounce booster (audio)
Synonyms of booster
: one that boosts: such as
a
: an enthusiastic supporter
b
: an auxiliary device for increasing force, power, pressure, or effectiveness
c
slang : shoplifter
d
: a radio-frequency amplifier for a radio or television receiving set
e
: the first stage of a multistage rocket providing thrust for the launching and the initial part of the flight
f
: a substance or dose used to renew or increase the effect of a drug or immunizing agent
especially : booster shot

Synonyms of booster

Relevance
See All Synonyms & Antonyms in Thesaurus

Examples of booster in a Sentence

These exercises are real metabolism boosters. Music is my favorite mood booster. A sincere compliment can be a true confidence booster. The university has a number of wealthy boosters who contribute generously each year. a new design for rocket boosters
Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
The statement said the weapon separated from its booster rocket at the planned altitude, then descended and maneuvered both vertically and horizontally before hitting a test target. — ABC News, 8 Oct. 2026 The anti-catalog exposed, after the fact of the Bicentennial, the grotesqueries of corporate beneficence and private boosters that had supplemented the government’s project. — Anna Kornbluh, ARTnews.com, 7 Oct. 2026 During the launch, a chunk of insulating foam broke off of the external tank and hit the bottom of the rocket booster, leaving a huge dent. — Tariq Malik, Space.com, 7 Oct. 2026 Navy weapon gets booster The motor will support a common architecture intended to replace single-purpose interceptors. — Aamir Khollam, Interesting Engineering, 7 Oct. 2026 See All Example Sentences for booster

Word History

First Known Use

1888, in the meaning defined above

Time Traveler
The first known use of booster was in 1888

Phrases Containing booster

Rhymes for booster

See All Rhymes for booster

Browse Nearby Words

boost
booster
booster battery
See all Nearby Words

Cite this Entry

“Booster.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/booster. Accessed 14 Oct. 2026.

Copy Citation

Kids Definition

booster

noun
boost·​er ˈbü-stər How to pronounce booster (audio)
1
: one that boosts
2
: an enthusiastic supporter
3
: booster shot
4
: a device for strengthening radio or television signals
5
: the first stage of a multistage rocket providing force for the launching and the first part of the flight

Medical Definition

booster

noun
boost·​er ˈbü-stər How to pronounce booster (audio)
: a substance or dose used to renew or increase the effect of a drug or immunizing agent: such as
a(1)
: booster shot
(2)
: booster dose
b
: synergist sense 1
a chemical acting as a booster to sulfa drugs
Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!

Last Updated: - Updated example sentences

More from Merriam-Webster

Word of the Day

Listen to the pronunciation of deportment

See Definitions and Examples »

Popular in Grammar & Usage

See More

Do You Need a New Language Peeve?

The Exceptions of '-s' and '-es' Plurals

Merriam-Webster’s Great Big List of Words You Love to Hate

Is it 'nerve-racking' or 'nerve-wracking'?

What's the difference between 'fascism' and 'socialism'?
See More

Popular in Wordplay

See More

The Real Origin of 'Supercalifragilistic'

9 Words That Sound Like Insults But Aren't

7 Words for Bad Endings and Rough Situations

The Words of the Week - Oct. 9

Why do we call it a 'flea market'?
See More

Popular

See More

Do You Need a New Language Peeve?

The Real Origin of 'Supercalifragilistic'

9 Words That Sound Like Insults But Aren't
See More

Games & Quizzes

See All
Play Quordle: Guess all four words in a limited number of tries. Each of your guesses must be a real 5-letter word.
Quordle Can you solve 4 words at once?
Play Blossom: Solve today's spelling word game by finding as many words as you can using just 7 letters. Longer words score more points.
Blossom Pick the best words!
Play Missing Letter: a crossword with a twist. Each of the 25 puzzle words start with a different letter of the alphabet. Which letter is missing?
The Missing Letter A daily crossword with a twist
a cup of tea and a golf ball on tee side by side
Quiz: Sounds Like... Choose the word that sounds like it fits the clue...
See All