The policeman called for 'backup' [=called for other police to come and help him] because the suspect was carrying a gun.
There was a traffic 'backup' [=('Brit') 'tailback'] for miles on the road because of the accident.
His role on the team is to be a 'backup' to the regular quarterback.
(..) I'm trying to get my GED. Hi. Robbie's going to go to medical school if it kills both of us. I was kind of thinking I'd be a vet. Yeah. Well, that's a good backup if you crap out on medical school. We're going to need the tutor's name, address, all that stuff. It's Andrew Hopp. (..)2008 TvShow: Bones Title: The Finger in the Nest Season: 4 Episode 3