Source : Free On-Line Dictionary of Computing

database machine
     
        A computer or special hardware that stores and retrieves data
        from a {database}.  It is specially designed for database
        access and is coupled to the main ({front-end}) computer(s) by
        a high-speed channel.  This contrasts with a {database
        server}, which is a computer in a {local area network} that
        holds a database.  The database machine is tightly coupled to
        the main CPU, whereas the database server is loosely coupled
        via the network.