an extra engine on a spacecraft that gives it enough power to leave the Earth’s atmosphere
Origin and usage
The noun booster comes from the verb boost, which originally meant to push or lift from behind. Both verb and noun are comparatively recent, having been first used in American English in the early and late 19th century respectively. The meaning related to spacecraft and rockets dates from 1944.
Booster has a number of different meanings. Originally meaning ‘someone who boosts something’ it was first used to refer to an auxiliary rocket that gives initial power to a rocket or missile during the Second World War. The boosters on a spacecraft give it an initial surge of speed that allows it to leave the Earth’s atmosphere; these engines are then jettisoned. Other meanings include a small extra amount of a drug given to ensure that the original dose continues to be effective, and something that makes you feel more confident, healthy, etc. Such things can be referred to as a confidence booster, a morale booster and so on. Booster is one of many entries in Macmillan Dictionary where the information given varies depending on whether you choose the British or the American version. The order of senses is different in the American entry and it also contains an extra meaning: someone who publicly supports a person, plan, or organization, with the example ‘The new airport, say its boosters, would do a lot for the local economy’. American English has another, informal, sense which is not currently covered in Macmillan Dictionary. To boost is to steal, and a booster is someone who steals something.
“At training, I consider myself a bit of a morale booster. I take a pack of lollies just to boost the boys’ morale.”
(Nick Cummins, athlete)
“I think it’s important to play. I don’t think the manager needs to give you a confidence booster and say, ‘You’re my main man; you’re the best.’ Everyone wants to play.”
(Daniel Sturridge, footballer
orbiter, shuttle, space capsule, rover