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

Allows high school coaches to receive additional compensation from funds raised by boosters and other support organizations (SB 538). — Cbs Miami Team, CBS News, 25 June 2026

Created by the makers of Korea’s buzzy Rejuran in-office skin boosters, the Turnover Ampoule offers a needle-free way to tap into the ingredient’s glow-boosting benefits at home. — Christa Joanna Lee, Allure, 24 June 2026

Adolescents should then receive a Tdap or tetanus, diphtheria and acellular pertussis booster at age 11 or 12. — Faye Chiu, CNN Money, 23 June 2026

This will be the 29th flight for this particular booster, tail number 1078, whose previous experience includes NASA's Crew-6 launch to the International Space Station, a Space Force mission and 23 Starlink launches, among others. — Josh Dinner, Space.com, 22 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