: 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
Her signature spin move and sleight-of-hand dribbling are slow-motion mood boosters.
—
Steven Louis Goldstein, New York Times, 2 Oct. 2025
On September 29, around 6 pm local time, a large solid-fuel booster was launched from northern China, following a path that maximized its visibility across several provinces.
—Kapil Kajal, Interesting Engineering, 1 Oct. 2025
The vehicle consists of two stainless-steel elements, both of which are designed to be fully reusable — a first-stage booster called Super Heavy and an upper stage known as Starship, or Ship for short.
—Mike Wall, Space.com, 30 Sep. 2025
Firefly Aerospace — The space technology company’s stock fell 21% after one of its rocket boosters exploded during preflight testing at its Texas facility.
—Fred Imbert, CNBC, 30 Sep. 2025
See All Example Sentences for booster
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Steven Louis Goldstein, New York Times, 2 Oct. 2025
On September 29, around 6 pm local time, a large solid-fuel booster was launched from northern China, following a path that maximized its visibility across several provinces.
—Kapil Kajal, Interesting Engineering, 1 Oct. 2025
The vehicle consists of two stainless-steel elements, both of which are designed to be fully reusable — a first-stage booster called Super Heavy and an upper stage known as Starship, or Ship for short.
—Mike Wall, Space.com, 30 Sep. 2025
Firefly Aerospace — The space technology company’s stock fell 21% after one of its rocket boosters exploded during preflight testing at its Texas facility.
—Fred Imbert, CNBC, 30 Sep. 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 8 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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