technoguy

A floppy disk is a data storage device that is composed of a disk of thin, flexible ("floppy") magnetic storage medium encased in a square or rectangular plastic shell. Floppy disks are read and written by a floppy disk drive or FDD, the latter initialism not to be confused with "fixed disk drive", which is an old IBM term for a hard disk drive.

craigdavid

A soft magnetic disk. It is called floppy because it flops if you wave it (at least, the 5??-inch variety does). Unlike most hard disks, floppy disks (often called floppies or diskettes) are portable, because you can remove them from a disk drive. Disk drives for floppy disks are called floppy drives. Floppy disks are slower to access than hard disks and have less storage capacity, but they are much less expensive. And most importantly, they are portable.