Definition of back up phrasal verb from the Oxford Advanced Learner's Dictionary

  

back up

 phrasal verb
phrasal verb
 
jump to other results
Phrasal Verbs

back up

|

back somethingup

 
jump to other results
to move backwards, especially in a vehicle You can back up another two feet or so. I backed the car up to the door.

    back up somebody

    |

    back up something

    |

    back somebody up

    |

    back something up

     
    jump to other results
  1. 1  to support somebody/something; to say that what somebody says, etc. is true I'll back you up if they don't believe you. The writer doesn't back up his opinions with examples.
  2. 2  to provide support for somebody/something two doctors backed up by a team of nurses The rebels backed up their demands with threats. related noun backup
(computing) to prepare a second copy of a file, program, etc. that can be used if the main one fails or needs extra support It's a good idea to back up your files onto a memory stick. related noun backup
See the Oxford Advanced American Dictionary entry: back up