A soft magnetic
disk. It is called
floppy because it flops if you wave it (at least, the 5¼-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.
Floppies come in three basic sizes: