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English definition of “backup”

backup

noun [C/U]  /ˈbækˌʌp/ us  

backup noun [C/U] (SUPPORT)

support or help, or someone or something that provides support or help: a backup generator They didn’t realize when they hired him that he had a backup band. We want to have the factual backup to make our case.

backup noun [C/U] (EXTRA COPY)

an extra copy of information on a computer that is stored separately: Did you make a backup of these files?
(Definition of backup from the Cambridge Academic Content Dictionary © Cambridge University Press)
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