high definition

noun

1. a system for screen display of images that are sharper and more detailed than normal, having many more than the standard number of scanning lines per frame: Most TV shows are available in high definition. Abbreviation: HDSee also high-definition television.
2. an audio system that reproduces sound with a high degree of accuracy and clarity: music recordings that use high definition.Abbreviation: HD
3. an optical system that produces very sharp images. Abbreviation: HD