Definition of backup
1a : one that serves as a substitute or support <I brought an extra pencil for backup.> <a backup plan>b : musical accompaniment <The tunes include banjo and guitar backup.>c : additional personnel who provide assistance <The police officer called for backup.>
2 : an accumulation caused by a stoppage in the flow <traffic backup>
3 : a copy of computer data (as a file or the contents of a hard drive) <I made a backup copy of the file.>; also : the act or an instance of making a backup
Examples of backup in a sentence
His role on the team is to be a backup to the regular quarterback.
We have an extra radio as a backup in case this one doesn't work.
We have an extra radio for backup.
He provides backup for the regular quarterback.
She sang backup on his CD.
First Known Use of backup
BACKUP Defined for English Language Learners
Definition of backup for English Language Learners
: a person or thing that can be used to replace or support another person or thing
: help or support provided by additional people or things
: a situation in which the flow of something (such as traffic) becomes blocked
BACKUP Defined for Kids
Definition of backup for Students
: a person who takes the place of or supports another <The guard called for a backup.>
Seen and Heard
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