Blu-ray Disc is an optical disk format for high-definition video. The standard was developed by the Blu-ray Disc Association (a consortium of companies, including Sony) and was released in 2006.
The discs themselves are the same size as DVD (120mm), but are capable of storing 25 GB per layer, with dual-layer discs being the industry standard for movies on Blu-ray Disc. Mini Blu-ray Discs (80mm) are also available, similar to MiniDVD.
Information is stored at a much higher density than DVD due to the use of blue lasers.
From its introduction until 2008, Blu-ray competed with HD-DVD, which was launched a few months prior to Blu-ray. By as early as January 2007, Blu-ray was outselling HD-DVD, helped by Sony including Blu-ray Disc support in the PlayStation 3.
As well as motion pictures, Blu-ray is used for distributing games for consoles such the Sony PlayStation 3 and 4, and the Xbox One, and recordable (BD-R) and rewritable versions (BD-RE) are also available for data or video storage. In 2013, High Fidelity Pure Audio was launched, using audio-only Blu-ray Discs.
Blu-ray Disc titles usually ship in packages similar to but slightly smaller than a standard DVD case, with the format prominently displayed across the top of the case. Some Blu-ray Discs come packaged with a DVD version of the film, as well as digital copies that can be played on computers.
Sources / Resources
Source: #FlashbackFriday Blu-ray Disc