εφεδρικός 英語で:

Tom and Mary were my backup singers back when I used to perform.

It's wise to make data backup on your computer every now and again.

There was a backup on the highway because of an accident.

Bring backup. Have you made a backup of that document?

There must be another backup.

It’s a good idea to save this file as backup.

Jane radioed the dispatcher for backup.

No problem. If X happens, we have Y as a backup.