Source : Free On-Line Dictionary of Computing

screen scraper
     
         A piece of software used to automate interaction
        between two computer systems through the terminal interface
        (designed for human use) of one of those systems.
     
        Typically, the screen scraper interacts with {terminal
        emulation} software to generate input to and process output
        from the "host" system through terminal screens.  Screen
        scrapers are advantageous when modifications to the host
        system are undesireable, when it is desireable to make use of
        the existing business and data integrity logic on the host,
        and when no other (peer-to-peer) interface method is
        available.
     
        Some products employ screen scraping combined with additional
        functionality which provides a {DBMS}-like or other
        specialised interface to the host.  The host system is often
        called a "{legacy} system" because it usually the older of the
        systems involved and based on older technology.
     
        (1995-04-19)