HD may refer to any of the following:
1. HD is an initialism used for hard drive, although you may also see it written as "HDD" for hard disk drive.
2. Short for high definition, HD describes a standard of digital video or audio. For video, it means 1280 x 720 pixels, or 720p on televisions. See the HDTV (high-definition television) definition for further information and related links.