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back up - definition and synonyms


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90% of the time, speakers of English use just 7,500 words in speech and writing. These words appear in red, and are graded with stars. One-star words are frequent, two-star words are more frequent, and three-star words are the most frequent.



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phrasal verb
Word Forms
present tense
I/you/we/theyback up
he/she/itbacks up
present participlebacking up
past tensebacked up
past participlebacked up
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  1. 1
    [transitive]back someone up to give support to someone by telling other people that you agree with them
    If I ask for more money will you back me up?
  2. 2
    [transitive] to show that an explanation or belief is probably true
    All the evidence backs up her story.
  3. 3
    [intransitive/transitive] to make a copy of information on your computer
  4. 5
    [intransitive] to move backward a short distance
    I need everyone to back up about 10 steps.
  5. 6
    [intransitive/transitive] to make a car go backward
    See if you can back up a little farther.
    back something up something: I’ll back the car up the driveway.
  6. 7
    [intransitive] used for telling someone to return to something that was said earlier
    Back up: didn’t you say they had already met?
See also main entry: back


a meal served in the evening which consists of foods traditionally eaten at breakfast

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troll factory

a company that pays its employees to write online comments in favour or against somebody or something posing as ordinary Internet users

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