Acronym for Redundant Array of Inexpensive/Independent Drives (or disks). The idea behind RAID is to spread data across multiple hard drives that act as one while keeping some redundancy so in case of one of the
drives failing, the data remains intact. There are different levels of RAID systems (RAID-0,1,2,3,4,5, 6, 10, 0+1, Drobo, etc.).