English

Verb

back up ‎(third-person singular simple present backs up, present participle backing up, simple past and past participle backed up)

1. (idiomatic, intransitive) To move backwards, especially for a vehicle to do so.

   That beeping sound indicates that the truck is backing up.‎

2. (idiomatic, transitive) To move a vehicle backwards.

   Back up the car a little, you're blocking the driveway.‎

   • 1898, Winston Churchill, chapter 5, in The Celebrity:

     We expressed our readiness, and in ten minutes were in the station wagon, rolling rapidly down the long drive, for it was then after nine. […] As we reached the lodge we heard the whistle, and we backed up against one side of the platform as the train pulled up at the other.

3. (idiomatic, intransitive) To undo one's actions.

   I couldn't see how to finish the project, so I backed up and tried it another way.‎

4. (idiomatic, intransitive) To reconsider one's thoughts.

   This isn't working. Let's back up and think about it.‎

5. (idiomatic, computing, transitive) To copy (data) as a security measure.

   Back up your documents folder before applying the update.‎

6. (idiomatic, transitive) To provide support or the promise of support.

   You should be careful. This guy is backed up by the local gang.‎

   When he said I wasn't there, I told him I was, and my buddy backed me up.‎

7. (idiomatic, intransitive, cricket) For the non-striker to take a few steps down the pitch, in preparation to taking a run, just as the bowler bowls the ball.
8. (idiomatic, intransitive, cricket) For a fielder to position himself behind the wicket (relative to a team-mate who is throwing the ball at the wicket) so as to stop the ball, and prevent overthrows.
9. (idiomatic, intransitive, of a blockage) To halt the flow or movement of something.

   When I flushed the toilet, the plumbing backed up and burst.‎

Translations

See also

• back down
• back into
• back off
• back out