HD

Hd, often written as HD, is an abbreviation with multiple meanings across different domains. The most widely recognized use is High Definition, a term describing video and imaging with higher resolution than standard definition. HD denotes clearer pictures and video with more detail, and it has become common in consumer media and devices.

In entertainment and display technology, HD commonly refers to resolutions such as 720p and 1080p. Full HD is specifically associated with 1080p, while 4K is usually labeled Ultra HD. Marketing terms like HD Ready and HDTV were used to separate capability tiers, particularly during the switch from standard definition to high definition.

In computing, HD can be shorthand for hard disk drive, referring to storage devices inside or attached to a computer. While some labels still use HD informally, the more precise term HDD (hard disk drive) is also common.

In medicine, HD most often stands for Huntington's disease, an inherited neurodegenerative disorder characterized by motor, cognitive, and psychiatric symptoms. It is caused by a genetic mutation and follows an autosomal dominant inheritance pattern.

In chemistry and astrophysics, HD refers to hydrogen deuteride, a diatomic molecule composed of hydrogen and deuterium. This molecule appears in spectroscopy and astrochemical models, including discussions of primordial chemistry in the early universe.

Other uses of HD exist in various fields, including as an abbreviation for phrases like high density or heavy duty, depending on the context. The meaning of HD is typically clarified by its specific domain and accompanying terminology.