back upverb

• 1

  To move backwards, especially for a vehicle to do so.

  • That beeping sound indicates that the truck is backing up.
  • 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.
• 2

  To move a vehicle backwards.

  • Back up the car a little, you're blocking the driveway.
• 3

  To undo one's actions.

  • I couldn't see how to finish the project, so I backed up and tried it another way.
• 4

  To reconsider one's thoughts.

  • This isn't working. Let's back up and think about it.
• 5

  computingengineeringmathematicsTo copy (data) so that it can be restored if the main copy is lost.

  • Back up your documents folder before applying the update.
• 6

  To provide support or the promise of support to.

  • 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

  ball-gamescricketgamesFor 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

  ball-gamescricketgamesFor 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.