deduplication - Computer Definition
(1) A method for compressing data by storing only changes to the original data. For example, when a document is created, it is stored as a regular, complete file. When changes are made, deduplication stores only the data that has been modified in a subsequent file with indexes to the original. The changes may be identified by bytes or blocks. See backup types.
(2) To remove duplicate records from a file or duplicate files in various storage locations.