HD

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HD

A prefix used to designate a star as listed in the Henry Draper Catalog.

HD

On drawings, abbr. for head.

HD

HD

(1) (High Definition) A resolution of 1280 x 720 pixels, which is the lower HD digital TV standard. See FHD, DTV, 720p and screen resolution.

(2) (High Definition) Typically refers to high-definition in the digital domain (for details, see HDTV). In the past, HD referred to several proprietary high-resolution video formats, both analog and digital, that exceeded the resolution of analog TV (NTSC, PAL). See HD formats, HD Radio, HD Audio and HDV.

(3) (Hard Disk, Hard Drive) The HD acronym is widely used in specifications; for example, 500GB HD (or 500GB HDD) refers to a 500 gigabyte hard disk. FD means floppy disk; now a distant memory. See magnetic disk.

(4) (High Density) An earlier designation for common floppy disk formats. For example, the 1.44MB 3.5" floppy was HD in contrast to the earlier double density (DD) 720KB format. For 5.25" floppies, the 1.2MB version was HD; the earlier 360KB was DD. See floppy disk.
References in periodicals archive ?
In less than 40 months, HD+ has developed from a start-up into an important factor in the German television market," said Wilfried Urner, Managing Director of the HD PLUS affiliate.
From May 1st, viewers with an HD+ receiver will have 32 encrypted and unencrypted free-to-air HD channels to choose from:
The DIRECTV HD Package includes ESPN HD, Discovery HD Theater(TM), Bravo HD+, HDNet, HDNet Movies, and HD Special Event programming for $10.