backup
//ˈbækˌʌp//
Noun
backupSingular
backupsPlural
1
A copy of computer data stored separately in case the original is lost or damaged.
I always keep a backup of my important files on an external hard drive.
2
A person or thing that can be used to replace or support another when needed.
We need a backup in case the main singer gets sick.
3
An accumulation or buildup, especially of traffic or work.
There was a backup of traffic on the highway due to the accident.
Adjective
backupCanonical form
1
Serving as a substitute or support in case of need.
Always keep a backup key in a safe place.