computer backup, backup - (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"

copy - a secondary representation of an original; "she made a copy of the designer dress"

counterpart, similitude, twin - a duplicate copy

match, mate - an exact duplicate; "when a match is found an entry is made in the notebook"

copying - an act of copying