This word is acceptable for play in the US dictionary that is being used in the following games:

• Lexulous
• Wordscraper
• Wordosaur

n. The action of defragmenting, particularly with respect to a computer disk or drive.

"I will run the program manually once in a while to check my disks and try to determine if the auto defragmentation is doing a good job, if is is, it will be one less thing that I will need to remember to do."

fragmentation