Back Something Up

to support or confirm something, especially by providing evidence or proof

The company backed up their claims with statistics.

She backed up her argument with several examples.

to move a vehicle backwards

Can you back up the car so I can get out?

She backed up the truck to the loading dock.

to make a copy of computer data, especially to prevent loss

Don't forget to back up your files before you leave for the day.

I backed up my phone before I reset it.