Source : WordNet®

input device
     n : a device that can be used to insert data into a computer or
         other computational device [syn: {data input device}]

Source : Free On-Line Dictionary of Computing

input device
     
         A {peripheral} used to transfer data from the
        outside world into a computer system.  Some input devices are
        operated directly by the user, e.g. {keyboard}, {mouse},
        {touch screen}, {joystick}, {digitising tablet}, {microphone};
        others are sensors or transducers which convert external
        signals into data, e.g. using an {ananlog to digital
        converter} (this would also be true of a microphone).  Other
        kinds of inputs are really one half of a bidirectional link
        with another computer or storage device, e.g. {serial line},
        {SCSI} interface.
     
        (1996-11-03)