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

• advocate
• advocator
• apostle
• backer
• champion
• espouser
• exponent
• expounder
• friend
• gospeler
• gospeller
• herald
• hierophant
• high priest
• paladin
• promoter
• proponent
• protagonist
• supporter
• true believer
• tub-thumper
• white knight

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

At the same time, Burgum is himself an avid horseman, hunter, skier, and hiker and has been a booster of outdoor recreation in North Dakota, creating the state’s Office of Outdoor Recreation and allocating $1.2 million in grants for trail building. —Frederick Reimers, Outside Online, 27 Jan. 2025

The study found that the size of the effect was greater than that of physical exercise, a more established mood booster. —Anna Cafolla, Vogue, 26 Jan. 2025

China successfully launched a classified satellite on Thursday (Jan. 23), but a spent booster from the mission fell shockingly close to a family home. —Andrew Jones, Space.com, 24 Jan. 2025

Along the way, Freeman has won over fans, students, alumni, administrators and boosters not only for winning but for his calm and positive demeanor, deep faith and interactions in private and public settings. —Tim Casey, Forbes, 20 Jan. 2025

Word History

First Known Use

1888, in the meaning defined above

Phrases Containing booster

• booster cushion
• booster dose
• booster seat
• booster shot

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