booster

noun

boost·​er ˈbü-stər 

: 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

Synonyms of booster

• proponent
• supporter
• advocate
• advocator
• exponent
• promoter

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

But officials did not prioritize reusability in Vulcan’s design, with no plans to reuse the rocket’s booster stage and only tentative plans to eventually recover and reuse Vulcan’s main engines. — Stephen Clark, ArsTechnica, 11 Sep. 2026

The band and football booster clubs will be selling cupcakes and keychains and stickers with his name and number on them to benefit the GoFundMe page that has been set up in Kufa’s name. — Lori Riley, Hartford Courant, 11 Sep. 2026

According to the district, the advertising could generate about $165,000 a year with funds split equally between the Naperville Central and Naperville North booster clubs. — Michelle Mullins, Chicago Tribune, 11 Sep. 2026

Prosecutors said professional shoplifters, or boosters, stole baby formula from major retailers and sold the formula to the defendants for about $10 per can. — Saleen Martin, USA Today, 11 Sep. 2026

Word History

First Known Use

1888, in the meaning defined above

Phrases Containing booster

• booster chair
• booster cushion
• booster dose
• booster seat
• booster shot

Rhymes for booster

• rooster

Kids Definition

booster

noun

boost·​er ˈbü-stər 

1

: one that boosts

2

: an enthusiastic supporter

3

: booster shot

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)

: booster shot

(2)

: booster dose

b

: synergist sense 1

a chemical acting as a booster to sulfa drugs