1. Standby, reserve or extra.
- I am only a backup player.
2. (computing) That is intended as a backup.
- Make a backup copy of that file.
1. an accumulation caused by clogging or a stoppage
- a traffic backup on the main street
- he discovered a backup in the toilet
2. someone who takes the place of another (as when things get dangerous or difficult)
3. a musical part (vocal or instrumental) that supports or provides background for other musical parts
4. (computer science) a copy of a file or directory on a separate storage device
- he made a backup in case the original was accidentally damaged or erased
5. the act of providing approval and support
Sentences with backup as a noun:
- If the goalkeeper is injured, we have a backup.
- After the power failure, we had to restore the database from backup.
- The blockage caused a backup in the plumbing.
- He's got a gun - you better send for backup.