: 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
No doubt that was our booster shot.
—
Miami Herald, 23 Oct. 2025
Throw in some texture and flavor boosters.
—Allison Forsyth, Health, 21 Oct. 2025
Today, crowds gather to witness towering SpaceX boosters return to Earth, where they’re caught by giant mechanical arms.
—Joshua Rothman, New Yorker, 21 Oct. 2025
Composed of a lower stage Super Heavy rocket booster and the upper stage Starship vehicle, the spacecraft is regarded as the world's largest rocket when fully stacked.
—Eric Lagatta, USA Today, 21 Oct. 2025
See All Example Sentences for booster
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Miami Herald, 23 Oct. 2025
Throw in some texture and flavor boosters.
—Allison Forsyth, Health, 21 Oct. 2025
Today, crowds gather to witness towering SpaceX boosters return to Earth, where they’re caught by giant mechanical arms.
—Joshua Rothman, New Yorker, 21 Oct. 2025
Composed of a lower stage Super Heavy rocket booster and the upper stage Starship vehicle, the spacecraft is regarded as the world's largest rocket when fully stacked.
—Eric Lagatta, USA Today, 21 Oct. 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 28 Oct. 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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