noun The first stage of a multistage rocket, providing primary or supplemental thrust for liftoff and early flight.
noun A motor-generator set used for voltage regulation in direct current electrical power circuits.
noun Someone who publicly promotes or endorses (something or someone); a fan or supporter.
noun A member of a booster club.
noun A booster dose.
When did you get your last tetanus booster?
noun A small quantity of a sensitive explosive that is triggered by a detonator and provides the energy needed to detonate a larger quantity of a less-sensitive explosive.