1/Used in military or police force: Reinforcements, support, help.
2/Computer using: create your secured data in case the computer goes down suddenly, mainly to prevent data loss.
2/Before installing Smart Windows Care, we strongly recommend you to back up you data first to prevent yourself from losing important data.
She had backup and i had nothing.
Let's get on the dancefloor dog. We can back-up on those hotties over there
You: "The bong prank - classic!"
Me: "I liked the bit where Backup attacked Felix Toombs and felix was screaming and dancing like a sissy with Backup on his arm!" *giggles*