to reorganize files on (a disk) so that the parts of each file are stored in contiguous sectors on the disk, thereby improving computer performance and maximizing disk space.
1992, in computer sense, from de- + fragment. Related: Defragmented; defragmenting.
defragmenter in Science
defragment
(dĭ-frāg'mənt) To reorganize the way information is stored on a computer disk so that all of the information belonging to a file is stored in a single, contiguous area the disk.