-tə(r) noun
( -s )
Usage: often attributive
1. : one that boosts
2. : an enthusiastic supporter or backer
a great booster for his home town
3. : an auxiliary device for increasing force, power, or pressure especially for the purpose of moving an object: as
a. : an additional locomotive on a train
b. : a hydraulic brake servomechanism
4. also booster pump : a pump used to increase the pressure of fluids
5. : a transformer for regulating or modifying a fluctuating or sagging voltage in an electric circuit
6. : a high explosive charge usually in the form of one or more pressed pellets in a cup or tube sensitive enough to be set off by a detonator and powerful enough to set off the main charge in a shell, mine, bomb, or other explosive device ; also : a device (as a tube) containing this charge
7. : a radio-frequency amplifier for intensifying signals picked up by a radio or television antenna before passing them on to the regular receiving set used especially where reception would otherwise be weak
8. : an auxiliary part of the propulsive system of a pilotless airplane or missile used to supply a part or all of the thrust during the launching and initial stage of flight : the first stage of a multistage rocket
9. : a pressure blower that draws in air or gas and expels it through an outlet pipe at a higher pressure
10. : a substance or dose used to renew or increase the effect of a drug or immunizing agent: as
a. : an injection of antigen given after completion of a primary course of immunization
the child was given a booster
a booster shot of diphtheria toxoid
— called also recall dose
b. : synergist 2
a chemical acting as a booster to sulfa drugs
11. slang
a. : thief ; especially : shoplifter
b. : shill