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

• 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

That number, while impressive, is far from SpaceX's reuse record of 30, which a Falcon 9 booster set this past Thursday (Aug. 28) on another Starlink mission. —Mike Wall, Space.com, 30 Aug. 2025

The university, the fans, and most important, boosters with deep pockets. —Matt Hayes, The Tennessean, 30 Aug. 2025

SpaceX is now aiming for at least 40 launches per Falcon 9 first stage, four times as many flights as the company's original target for Falcon 9 booster reuse. —Stephen Clark, ArsTechnica, 29 Aug. 2025

Snag their award-winning active face serum and their signature, Vitamin C powder booster, along with fresh finds, such as their corrective eye patches and overnight lip treatment. —Kristina Rutkowski, Vogue, 29 Aug. 2025

Word History

First Known Use

1888, in the meaning defined above

Phrases Containing booster

• 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