: 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
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
The booster's upper stage reached a preliminary orbit about nine minutes after leaving the ground.
—
Robert Z. Pearlman, Space.com, 26 July 2025
Contrary to what the boosters of the bill believe, the implications for related digital assets and the economy are very mixed at best.
—Vipin Bharathan, Forbes.com, 24 July 2025
The first-stage booster made its ninth flight landing on the droneship A Shortfall of Gravitas, marking its 100th booster catch.
—Richard Tribou, The Orlando Sentinel, 23 July 2025
The rocket, called Starship, is the largest, most powerful ever built, standing 403 feet tall with its booster.
—ArsTechnica, 22 July 2025
See All Example Sentences for booster
Examples are automatically compiled from online sources to
show current usage.
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Opinions expressed in the examples do not represent those of Merriam-Webster or its editors.
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Robert Z. Pearlman, Space.com, 26 July 2025
Contrary to what the boosters of the bill believe, the implications for related digital assets and the economy are very mixed at best.
—Vipin Bharathan, Forbes.com, 24 July 2025
The first-stage booster made its ninth flight landing on the droneship A Shortfall of Gravitas, marking its 100th booster catch.
—Richard Tribou, The Orlando Sentinel, 23 July 2025
The rocket, called Starship, is the largest, most powerful ever built, standing 403 feet tall with its booster.
—ArsTechnica, 22 July 2025
See All Example Sentences for booster
Cite this Entry
“Booster.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/booster. Accessed 29 Jul. 2025.
Copy CitationKids Definition
booster
noun
boost·er
ˈbü-stər 
1
: one that boosts
2
: an enthusiastic supporter
3
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
: a substance or dose used to renew or increase the effect of a drug or immunizing agent: such as
a(1)
(2)
b
: synergist sense 1
a chemical acting as a booster to sulfa drugs
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