back up

phrasal verb
Word forms "back up":
present tense I/you/we/they back up he/she/it backs up present participle backing up past tense backed up past participle backed up

1) back someone up

[transitive] 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) [transitive] to show that an explanation or belief is probably true

All the evidence backs up her story.

3) [intransitive/transitive] to make a copy of information on your computer

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

Traffic is backing up on all out-of-town routes.

Cars were backed up for miles.

a) if a toilet, sink, or drain backs up, or if it is backed up, water cannot flow through it because something is blocking it

b) if a system backs up, or if it is backed up, it has slowed down or stopped working because there is too much of something for it to deal with

Orders are really backed up this month.

5) [intransitive] to move backwards a short distance

I need everyone to back up about 10 paces.

6) [intransitive/transitive] to make a car go backwards

See if you can back up a bit further.

back something up something:

I'll back the car up the driveway.

7) [intransitive] mainly American used for telling someone to return to something that was said earlier

Back up: didn't you say they had already met?