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back up

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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

Related meanings

  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
    Synonyms and related words for this sense of back up
  4. 4
    [intransitive/transitive] if traffic backs up, or if it is backed up, the vehicles are in a long line and waiting to continue moving

    Cars were backed up for miles.

    Traffic is backing up on all routes out of town.

  5. 5
    [intransitive] to move backward a short distance

    I need everyone to back up about 10 steps.

  6. 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.

    Synonyms and related words for this sense of back up
  7. 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


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