A synthetic full or synthetic cumulative incremental backup is a backup assembled from previous backups. The backups include one previous, traditional full backup, and subsequent differential backups, and a cumulative incremental backup. (A traditional full backup means a non-synthesized, full backup.) A client can then use the synthesized backup to restore files and directories in the same way that a client restores from a traditional backup.

Synthetic backups can be written to tape or to disk storage units, or a combination of both.