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

Meanwhile, downtown-adjacent Brickell is a fintech favorite and home to firms like the hedge fund Citadel, owned by Griffin, one of Miami’s most prominent boosters. —Matthew Kronsberg, Architectural Digest, 6 Mar. 2026

Use hydrogen peroxide as a pre-wash treatment or booster to deodorize towels and bath mats. —Nishaa Sharma, The Spruce, 5 Mar. 2026

Collagen supplements have exploded in popularity, touted as everything from an anti-aging miracle to a muscle recovery booster. —Deirdre Bardolf, FOXNews.com, 5 Mar. 2026

Bouquets, real, faux, or on your manicure, are an instant serotonin booster. —Ariel Wodarcyk, InStyle, 5 Mar. 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