Dedicated vga and shared vga.

Dedicated means there's a separate video chip or card with at least some of its own memory.  Shared means the video is part of the chipset in the system, with no memory of its own (system memory is used).

Two things blur the lines:  very few notebooks outside of the very high end now have separate video cards - most video is built into the mainboard either way, and Vista uses a significant quantity of system RAM for video regardless of whether the video is discrete or integrated.