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

To address the steep terrain along the route, a new booster pump station will be built allowing water to be conveyed safely and efficiently across the mountain, according to the Barona website. —Julie Gallant, San Diego Union-Tribune, 23 Apr. 2026

That narrative has been hard to shake, despite there being little empirical evidence for the thesis so far and the fact that plenty of economists, enterprise tech analysts, and tech CEOs—including AI boosters such as Nvidia CEO Jensen Huang—think the narrative is wrong. —Jeremy Kahn, Fortune, 23 Apr. 2026

Unfortunately for boosters who enjoy bragging about their investments, only one team will win a national championship each year. —Trey Wallace Outkick, FOXNews.com, 22 Apr. 2026

Police said the investigation began in February when detectives were called to Chartiers Valley Middle School to help look into funds believed to be stolen from the booster fund. —Madeline Bartos, CBS News, 22 Apr. 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