The resolution is the accuracy of the image that the projector casts. Most projectors fall into two categories - SVGA (800 x 600 pixels) or XGA (1024 x 768 pixels). Similarly, most computers output a signal which is either SVGA or XGA.
The majority of dedicated home cinema projectors project a native 16:9 (widescreen) image and fall into one of three resolution categories - WVGA (854 x 480 pixels), WSVGA (1024 x 576 pixels) or WXGA (1280 x 720 pixels). The 'W' stands for 'Wide'.