Noun
the first stage of a multistage rocket
Source: WordNetAn O-ring seal in the right booster rocket failed at liftoff, leading to subsequent structural failures. Source: Internet
The unmanned craft was lifted into orbit by the specially designed Energia booster rocket. Source: Internet
Large pieces of the plutonium contaminated missile including pieces of the warhead, booster rocket, engine, re-entry vehicle and missile parts fell back on Johnston Island. Source: Internet