- 1 something that helps or encourages someone or something a great/tremendous/welcome boost The tax cuts will give a much-needed boost to the economy. Winning the competition was a wonderful boost to the team's morale.
- 2an increase in something a boost in car sales
- 3an increase in power in an engine or a piece of electrical equipment
- 4 an act of pushing someone up from behind He gave her a boost over the fence.