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

Trump remains data-center booster amid bipartisan opposition The rapid expansion of data centers, which house networks and services for digital information and services, is proving to be the rare issue that cuts through party lines. — Joey Garrison, USA Today, 28 Aug. 2026

This will be the first flight for one of the boosters while the other supported two previous Falcon Heavy launches. — Richard Tribou, The Orlando Sentinel, 28 Aug. 2026

The Russian Defense Ministry said that its forces overnight struck a warehouse in the Kyiv region that stores Ukraine’s Flamingo cruise missiles and fuel for rocket boosters. — Hanna Arhirova, Los Angeles Times, 28 Aug. 2026

The Russian Defense Ministry said its forces overnight struck a warehouse in the Kyiv region that stores Ukraine’s Flamingo cruise missiles and fuel for rocket boosters. — ABC News, 28 Aug. 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