[¦graf·ə·kəl ¦vizh·ə·wəl di′spla di‚vīs] (computer science) A computer input-output device which enables the user to manipulate graphic material in a visible two-way, real-time communication with the computer, and which consists of a light pen, keyboard, or other data entry devices, and a visual display unit monitored by a controller. Also known as graphoscope.