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

During the meeting, Vice Mayor John Herbst floated the idea of using developer permit fees to fund the boosters as a potential solution. —Niurys Robaina, Miami Herald, 4 Dec. 2025

The complex was renamed Carter Field in 1950, after the Star-Telegram publisher, civic booster and aviation enthusiast. —Matt Leclercq, Fort Worth Star-Telegram, 3 Dec. 2025

Reusable rockets form the backbone of the success of Elon Musk’s firm SpaceX, which hashed out how to land and reuse rocket boosters nearly a decade ago and now dominates the global launch market. —Simone McCarthy, CNN Money, 3 Dec. 2025

Plenty of TikTok videos tout coffee as a bloom booster for Christmas cacti, too. —Leanne Potts, Better Homes & Gardens, 3 Dec. 2025

Word History

First Known Use

1888, in the meaning defined above

Phrases Containing booster

• 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