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English definition of “back sth up”

back sth up

phrasal verb with back     /bæk/ verb
C2 to prove something is true: His claims are backed up by recent research.Proving and disproving B2 to make an extra copy of computer information: Make sure you back up your files. → See also backupOperating computers
(Definition of back sth up from the Cambridge Advanced Learner's Dictionary & Thesaurus © Cambridge University Press)
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