back up

verb12

1. •
   To move backwards, especially for a vehicle to do so.

   • That beeping sound indicates that the truck is backing up.
2. •
   To move a vehicle backwards.

   • Back up the car a little, you're blocking the driveway.
3. •
   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.
4. •
   To copy (data) so that it can be restored if the main copy is lost.

   • Back up your documents folder before applying the update.
5. •
   To halt the flow or movement of something.

   • When I flushed the toilet, the plumbing backed up and burst.
6. •
   To fill up because of a backlog.

   • WAITRESS: Hurry up with those drinks, Lucy. We're backing up. (Grabs the drinks LUCY has poured.) What are you doing? These are regular. They all ordered large. — 1995
7. •
   To undo one's actions.

   • I couldn't see how to finish the project, so I backed up and tried it another way.
8. •
   To reconsider one's thoughts.

   • This isn't working. Let's back up and think about it.
9. •
   If a property backs up to another property, that means it abuts or shares a border with another property.

   • We bought this house specifically because it backs up to our son's school.
10. •
    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.
11. •
    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.
12. •
    (no longer used) To run a printing press in reverse.