: 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
Consider taking a winter storm kit along with you, including such items as tire chains, booster cables, flashlight, shovel, blankets and extra clothing.
—
Ca Weather Bot, Sacbee.com, 9 Apr. 2026
Notably, people will likely need boosters before each tick season, says Ondrej Hajdusek, a parasite biologist at the Czech Academy of Sciences, who co-authored a Comment piece about the phase 1 trial of the new vaccine in the Lancet.
—Tara Haelle, Scientific American, 9 Apr. 2026
Standing in the outfield, several players stopped and watched as the rocket’s massive boosters, in all their fiery glory, roared on the huge screen.
—Lisa Gutierrez, Kansas City Star, 9 Apr. 2026
Singles of what’s in the kit are also available, plus a mask, brow density booster, oil, serum and more.
—Tory Johnson, ABC News, 8 Apr. 2026
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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Ca Weather Bot, Sacbee.com, 9 Apr. 2026
Notably, people will likely need boosters before each tick season, says Ondrej Hajdusek, a parasite biologist at the Czech Academy of Sciences, who co-authored a Comment piece about the phase 1 trial of the new vaccine in the Lancet.
—Tara Haelle, Scientific American, 9 Apr. 2026
Standing in the outfield, several players stopped and watched as the rocket’s massive boosters, in all their fiery glory, roared on the huge screen.
—Lisa Gutierrez, Kansas City Star, 9 Apr. 2026
Singles of what’s in the kit are also available, plus a mask, brow density booster, oil, serum and more.
—Tory Johnson, ABC News, 8 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 15 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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