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

• advocate
• advocator
• apostle
• backer
• champion
• espouser
• exponent
• expounder
• friend
• gospeler
• gospeller
• herald
• hierophant
• high priest
• paladin
• promoter
• proponent
• protagonist
• supporter
• true believer
• tub-thumper
• white knight

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

For one thing, there’s the revenue-sharing component, in which schools will be able to directly spend $20.5 million on their rosters (in all sports) without having to depend on fan/booster donations. —Stewart Mandel, The Athletic, 19 Feb. 2025

The first-stage booster for the mission made its 16th launch. —Richard Tribou, Orlando Sentinel, 18 Feb. 2025

One source with knowledge of the second booster's production said October might be a more reasonable timeframe for the second launch. —Eric Berger, Ars Technica, 14 Feb. 2025

The 6-foot-6 point guard with rocket boosters for legs and all-league caliber defense has been one of the NBA’s breakout stars this season, averaging 13.7 points, 8.1 rebounds and 3.4 assists per game while providing jaw-dropping highlights nightly. —Joseph Dycus, The Mercury News, 14 Feb. 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