4K resolution refers to a horizontal display resolution of approximately 4,000 pixels.[1] Digital television and digital cinematography commonly use several different 4K resolutions. In television and consumer media, 3840 × 2160 (4K UHD) with a 16:9 aspect ratio is the dominant 4K standard, whereas the movie projection industry uses 4096 × 2160 (DCI 4K).
The 4K television market share increased as prices fell dramatically throughout 2013 and 2014.[2][3]
4K resolution: A general term referring to any digital image containing an X resolution of approximately 4096 pixels.