Resolution (Display Resolution) - Resolution refers to the sharpness and clarity of an image. TV resolution has typically been expressed as the number of (visible) lines in the picture. Standard analog TV has a resolution of 496 (NTSC) or 575 (PAL, SECAM) visible lines. The ATSC standard for HDTV has a resolution of 1080 visible lines.
    
The resolution can also be expressed as the number of individual pixels comprising the picture. Good NTSC color TV's have a resolution of 720 by 486 (that's 720 horizontal pixels by 486 vertical pixels), corresponding to the physical number of pixels in the screen. This is not impressive compared to the resolution of computer monitors, which are commonly 800 by 600, 1024 by 768 or better. The low resolution of standard TV is a major drawback of using it as a web browser.
    
HDTV-ready TV sets have smaller, square pixels rather then the rectangular ones on a standard TV. As of the time of this writing, these could display at resolutions of around 1920 by 1080.
https://en.wikipedia.org/wiki/Display_resolution