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

Its two outer booster engines were discarded during flight, while the central sustainer continued operating and later helped the converted Atlas launch John Glenn into orbit. — Atharva Gosavi, Interesting Engineering, 19 Sep. 2026

A lot of missions for a single rocket … SpaceX launched the mPOWER-F mission using the Falcon 9 first stage booster with the tail number B1080. — Eric Berger, ArsTechnica, 18 Sep. 2026

Just like there are today, there were doomers and skeptics, utopian boosters and scientists pleading for calm. — J.d. Capelouto, semafor.com, 18 Sep. 2026

Yaeger is the head of the booster organization for the fictional South Georgia Catfish football team. — Mason Leib, ABC News, 17 Sep. 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