4K resolution is a generic term for display devices or content having horizontal resolution on the order of 4,000 pixels.
Several 4K resolutions exist in the fields of digital television and digital cinematography. In the movie projection industry, Digital Cinema Initiatives is the dominant 4K standard.
The television industry has adopted ultra high definition television as its 4K standard. As of 2013, some UHDTV models are available to general consumers for under $1000. However, due to lack of available content, 4K television has yet to achieve mass market appeal. Using horizontal resolution to characterize the technology marks a switch from the previous generation, high definition television, which categorized media according to vertical resolution (1080i, 720p, 480p, etc.). The top-end regular HDTV format, 1080p, qualifies as 2K resolution, having a horizontal resolution of 1920 pixels, with a vertical resolution of 1080 pixels.