backup

A musical part (vocal or instrumental) that supports or provides background for other musical parts.

(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”

The act of providing approval and support.

Someone who takes the place of another (as when things get dangerous or difficult).

An accumulation caused by clogging or a stoppage.

“a traffic backup on the main street”

“he discovered a backup in the toilet”