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

Consider taking a winter storm kit along with you, including such items as tire chains, booster cables, flashlight, shovel, blankets, and extra clothing. —Amanda Greenwood, MSNBC Newsweek, 26 Nov. 2025

Those pan drippings are the ultimate foundation of classic gravy, and can be an incredible flavor booster for stuffing, sides, and more. —Katie Rosenhouse, Southern Living, 25 Nov. 2025

With both hearts beating, the second heart acted as a booster for the first. —Scott Lafee, San Diego Union-Tribune, 25 Nov. 2025

The theoretical goal is to achieve extremely high supersonic speeds, requiring only a small onboard booster rocket to complete orbital insertion for payloads such as satellites or supplementary equipment (it is not designed for human passengers). —Mrigakshi Dixit, Interesting Engineering, 24 Nov. 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