The term 4K in digital cinema pertains to projectors with a resolution of 4096 x 2160, offering four times the pixel count of Full HD (1920 x 1080). This higher resolution provides a more detailed and immersive viewing experience for audiences in cinemas.
Source: https://www.openpr.com/news/4226350/global-pay-tv-market-major-trends-reshaping-the-future-of