boost·​er ˈbü-stər How to pronounce booster (audio)
: one that boosts: such as
: an enthusiastic supporter
: an auxiliary device for increasing force, power, pressure, or effectiveness
slang : shoplifter
: a radio-frequency amplifier for a radio or television receiving set
: the first stage of a multistage rocket providing thrust for the launching and the initial part of the flight
: a substance or dose used to renew or increase the effect of a drug or immunizing agent
especially : booster shot

Example Sentences

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 rates of booster shots in these age groups are much lower. Lynn R. Goldman And Amanda D. Castel, STAT, 11 Nov. 2022 Vaxzevria isn’t alone in facing lower demand around the world amid lackluster enthusiasm for fall booster shots. Denise Roland, WSJ, 10 Nov. 2022 The threat of another surge isn’t exactly lighting a fire under Americans to get the new booster shots. Karen Kaplanscience And Medicine Editor, Los Angeles Times, 1 Nov. 2022 The latest booster shots target two subvariants of the omicron variant, which are versions of the virus that are currently most dominant in the United States and around the world, according to the White House. Ben Gittleson, ABC News, 25 Oct. 2022 Both groups measured antibodies about three to five weeks after people received booster shots. Ryan Cross,, 25 Oct. 2022 Most people can get flu shots and COVID-19 booster shots at no charge. Julie Washington, cleveland, 20 Oct. 2022 The updated Covid booster shots, which became available just last month, target both BA.4 and BA.5. Erika Edwards, NBC News, 19 Oct. 2022 Sponsored by the Oregon Health Authority, the comics focused on topics ranging from preventing the spread of COVID, to living with the virus and getting booster shots. Destiny Johnson |, oregonlive, 18 Oct. 2022 See More

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'booster.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

Word History

First Known Use

1888, in the meaning defined above

Time Traveler
The first known use of booster was in 1888

Dictionary Entries Near booster

Cite this Entry

“Booster.” Dictionary, Merriam-Webster, Accessed 1 Dec. 2022.

Kids Definition



boost·​er ˈbü-stər How to pronounce booster (audio)
: one that boosts
: an enthusiastic supporter
: a device for strengthening radio or television signals
: the first stage of a multistage rocket providing force for the launching and the first part of the flight

Medical Definition



boost·​er ˈbü-stər How to pronounce booster (audio)
: a substance or dose used to renew or increase the effect of a drug or immunizing agent: such as
: synergist sense 1
a chemical acting as a booster to sulfa drugs

More from Merriam-Webster on booster

Last Updated: - Updated example sentences
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