back up

Meaning

To make a copy of computer files so that you do not lose them.

Examples

1. Back up your photos before you update the phone. US UK
2. I back up my laptop every Friday. US UK
3. Did you back the files up? US UK

How to use it

A second meaning is to support a person or a statement: She backed up her argument with facts. The noun is backup, written as one word: make a backup. The verb is two words.

Common mistake

Not: Please backup your files.
Say: Please back up your files. (The verb is two words. The noun is one word: backup.)