: 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 Fab Five was estranged for many years because of Webber’s association with a Michigan booster.
—
Colleen Kane, Chicago Tribune, 3 Apr. 2026
First up will be the segments for the two solid rocket boosters, followed by the core stage, upper stage and Orion spacecraft.
—Richard Tribou, The Orlando Sentinel, 3 Apr. 2026
The moon’s clash with Jupiter is a confidence booster, but don’t be shocked by a mid-day mood swing.
—Usa Today, USA Today, 2 Apr. 2026
That power came from two solid rocket boosters and four RS-25 engines, which lifted the rocket into Earth orbit.
—Briana Alvarado, ABC News, 2 Apr. 2026
See All Example Sentences for booster
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Colleen Kane, Chicago Tribune, 3 Apr. 2026
First up will be the segments for the two solid rocket boosters, followed by the core stage, upper stage and Orion spacecraft.
—Richard Tribou, The Orlando Sentinel, 3 Apr. 2026
The moon’s clash with Jupiter is a confidence booster, but don’t be shocked by a mid-day mood swing.
—Usa Today, USA Today, 2 Apr. 2026
That power came from two solid rocket boosters and four RS-25 engines, which lifted the rocket into Earth orbit.
—Briana Alvarado, ABC News, 2 Apr. 2026
See All Example Sentences for booster
Cite this Entry
“Booster.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/booster. Accessed 5 Apr. 2026.
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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