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

The first-stage boosters made their 6th and final flights with no recovery. — Richard Tribou, The Orlando Sentinel, 29 June 2026

Next steps ahead of that launch will include rolling the mission's Super Heavy booster to the pad at Starbase for engine tests of its own. — Josh Dinner, Space.com, 2 July 2026

Pooling television rights between conferences, a pet project of Texas Tech board chairman and mega-booster Cody Campbell, has been done before. — Sam Khan Jr, New York Times, 1 July 2026

The vessels are an integral part of SpaceX's reusability philosophy, especially for missions that cannot carry enough fuel for a booster to return and land back at the launch site. — Eric Lagatta, USA Today, 30 June 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