High-definition television (HDTV) is a television broadcasting system which uses a higher resolution than a normal television. With HDTV, people can see sharper pictures than with old television, giving a more vivid and clear screen.
Most HDTV systems use digital signals with a 16:9 aspect ratio (width to height). This is different to SDTV (standard-definition television) which uses analog signals and a 4:3 aspect ratio.