Source : WordNet®

secondary storage
     n : a data storage device that is not the main memory of a
         computer [syn: {auxiliary storage}, {external storage}]

Source : Free On-Line Dictionary of Computing

secondary storage
     
         Any {non-volatile} storage medium that is not
        directly accessible to the {processor}.  Memory directly
        accessible to the processor includes {main memory}, {cache}
        and the {CPU} {registers}.  Secondary storage includes {hard
        drives}, {magnetic tape}, {CD-ROM}, {DVD drives}, {floppy
        disks}, {punch cards} and {paper tape}.
     
        Secondary storage devices are usually accessed via some kind
        of controller.  This contains registers that can be directly
        accessed by the CPU like main memory ("{memory mapped}").
        Reading and writing these registers can cause the device to
        perform actions like reading a block of data off a disk or
        rewinding a tape.  See also {DMA}.
     
        Programs and data stored in secondary storage must first be
        loaded into main memory before the processor can use them.
     
        (1997-11-05)