The primary computer storage device, which spins, reads and writes one or more fixed disk platters. The terms "hard drive" and "hard disk" are synonymous; however, a "drive" technically refers to the entire unit that holds one or more "disk" platters. The word "hard" came about to refer to the rigid platters made of aluminum or glass in contrast to floppy disks made of flexible plastic.
Increasingly, hard drives are giving way to solid state drives (SSDs) in desktop computers but especially in laptops. See hard disk
, hard disk interfaces
and floppy disk