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[boo-ster] /ˈbu stər/
a person or thing that boosts, especially an energetic and enthusiastic supporter.
Electricity. a device connected in series with a current for increasing or decreasing the nominal circuit voltage.
Railroads. any machine, device, phenomenon, etc., that helps to move a train, as a tailwind, downgrade, roller bearings, or especially a helper locomotive.
Military. an explosive more powerful than a primer, for ensuring the detonation of the main charge of a shell.
  1. a rocket engine used as the principal source of thrust in the takeoff of a rocket or missile.
  2. the first stage containing this engine and its fuel supply, which may or may not be detached from the rocket when the fuel has been consumed.
Medicine/Medical.. Also called booster dose, booster shot. a dose of an immunizing substance given to maintain or renew the effect of a previous one.
Pharmacology. a chemical compound, medicinal substance, or the like, that serves as a synergist.
a radio-frequency amplifier for connecting between a radio or television antenna and the receiving set to intensify the received signal.
an auxiliary pump, used in a pipeline or other system, to add to or maintain a prevailing amount of pressure or vacuum.
Slang. a shoplifter or petty thief.
Origin of booster
An Americanism dating back to 1885-90; boost + -er1
Related forms
boosterish, adjective Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2018.
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Examples from the Web for booster
Contemporary Examples
Historical Examples
  • The primary—ah, booster, as you say, breaks free at twelve miles.

    The Big Tomorrow Paul Lohrman
  • Like the rest of you, I knew nothing of the true action of the booster.

    The Long Voyage Carl Richard Jacobi
  • They haven't got the booster or anything like it, or they'd have used it.

    Masters of Space Edward Elmer Smith
  • One is reduced to the figures of the real estate "booster" for terms of proportion.

    California Mary Austin
  • "Be a booster," it advises, and no one can say that it does not live up to its principles.

    Abroad at Home

    Julian Street
British Dictionary definitions for booster


a person or thing that supports, assists, or increases power or effectiveness
Also called launch vehicle. the first stage of a multistage rocket
(radio, television)
  1. a radio-frequency amplifier connected between an aerial and a receiver to amplify weak incoming signals
  2. a radio-frequency amplifier that amplifies incoming signals, retransmitting them at higher power
another name for supercharger
short for booster dose
(slang, mainly US) a shoplifter
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
© William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
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Word Origin and History for booster

1890, "one who boosts" something, agent noun from boost (v.). Electrical sense is recorded from 1894. Young child's booster chair is attested under that name from 1960.

Online Etymology Dictionary, © 2010 Douglas Harper
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booster in Medicine

booster boost·er (bōō'stər)
An additional dose of an immunizing agent, such as a vaccine or toxoid, given at a time after the initial dose to sustain the immune response elicited by the previous dose of the same agent. Also called booster dose, booster shot.

The American Heritage® Stedman's Medical Dictionary
Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
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booster in Science
An additional dose of an immunizing agent, such as a vaccine or toxoid, given at a time period of weeks to years after the initial dose to sustain the immune response elicited by the first dose. Tetanus, diphtheria, and measles vaccines are commonly given in booster doses.
The American Heritage® Science Dictionary
Copyright © 2002. Published by Houghton Mifflin. All rights reserved.
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Slang definitions & phrases for booster



  1. A shoplifter; pilferer: Got a booster for you. The chunky girl in blue at the lace counter/ He knew they couldn't be boosters or creepers (1908+)
  2. A huckster's or auctioneer's assistant who pretends to buy in order to stimulate others; shill (1905+ Carnival)
  3. A person who praises extravagantly; fan (1890+)
The Dictionary of American Slang, Fourth Edition by Barbara Ann Kipfer, PhD. and Robert L. Chapman, Ph.D.
Copyright (C) 2007 by HarperCollins Publishers.
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