High density digital versatile disc which uses blue lasers similar to that of Blu-ray discs. Being proposed as the standard for high-definition DVD and is promoted by Toshiba, NEC and Sanyo
The name given to a High Density DVD format, being studied by the DVD Forum to store HDTV content. Proposed by Toshiba and NEC it was originally called AOD ( Advanced Optical Disc) and offers a capacity of 15 GB per layer, 20 GB for re-writable versions. HD-DVD is one of two options being developed to meet the requirements of HDTV. The other is Blu-ray.
Is the next generation high definition DVD player.
High Definition Digital Versatile Disc: the official, DVD Forum approved, next-generation DVD format, originally jointly specified and proposed by Toshiba and NEC.
Short for High Definition-DVD, a generic term for the technology of recording high-definition video on a Digital Versatile Disc or DVD. HD-DVD are normally capable of storing between two and four times as much data as standard DVD. There is a competition between two main technologies: AOD (jointly developed by NEC and Toshiba) and Blu-ray (a consortium formed by Sony, Samsung, Sharp, Thomson, Hitachi, Matsushita, Pioneer + Philips, Mistubishi and LG Electronics.)
HD DVD (High Density DVD, High-Definition DVD or High Definition Digital Video Disc) is a high-density optical disc format designed for the storage of high-definition video and data. It is currently in a format war against the Blu-ray disc, an optical disc which can hold more data than HD DVD. The HD DVD name is derived from its origination as a high-definition extension of the DVD optical disc format. An HD DVD disc can store substantially more data than a standard DVD, because of the shorter wavelength (405 nm) of the blue-violet laser (DVDs use a 650-nm-wavelength red laser and CDs an infrared 780 nm laser), which allows more information to be stored digitally in the same amount of physical space. In comparison to Blu-ray Disc, which also uses a blue laser, HD DVD has less information capacity per layer (15 gigabytes instead of 25). HD DVD shares the same basic disc structure as a standard DVD: back-to-back bonding of two 0.6 mm thick, 120 mm diameter substrates.  The 30 GB dual-layer HD DVDs have been used on nearly every movie released in this format.
DVD standard that supports high def video encoding.
HD-DVD (HD stands for both high-density and high-definition) was under development before DVD came out. It finally emerged in 2003. Some high-definition versions of HD-DVD use the original DVD physical format but depend on new video encoding technology such as H.264 to fit high-definition video in the space that used to hold only standard-definition video. High-density formats use blue or violet lasers to read smaller pits, increasing data capacity to around 15 to 30 GB per layer. High-density formats use high-definition MPEG-2 video (for compatibility with ATSC and DVB HD broadcasts) and may also use advanced encoding formats, probably supporting 1080p24 video. HD discs will not play on existing players. As of early 2003 there are five proposals for HD-DVD, with the possibility of others: HD-DVD-9, aka HD-9 Advanced Optical Disc (AOD) Blu-ray Disc (BD) Blue-HD-DVD-1 Blue-HD-DVD-2 http://www.dvddemystified.com/dvdfaq.html#3.13
High-Definition DVD. Similar to current DVD technology, but the discs can hold much more data (15 GB on a single-layer disc); it is one of two technologies in the new DVD “format war” (Blu-Ray being the other).