Definition of UHD in English:

UHD

noun

mass noun
  • (in digital television and cinematography) technology, equipment, or content providing a very sharp image quality.

    • ‘you'll get much sharper results by shooting in UHD’
    • ‘the benefits of UHD are really only visible on the largest screens’
    • ‘high-end UHT televisions’

Origin

1960s abbreviation of ultra-high density.