4K, 4-K or 4k may refer to: 4000 (number) Four kibibytes (4 × 1024 bytes, better written 4 KiB) 4K disk sector size (Advanced Format) 4K demoscene compo, a computer art competition using programs limited to 4 kibibytes The Java 4K Game Programming Contest 4K resolution, a collective term for digital video formats having a horizontal resolution of approximately 4,000 pixels 4K UHDTV, an ultra-high-definition television format 4K, the IATA airline code for Askari Aviation 4K, an alternative name for Cuatro Cabezas (Four Heads), an Argentine multimedia production company. 4K, model of Toyota K engine 4K, the production code for the 1976 Doctor Who serial The Brain of Morbius 4KScore test for prostate cancer screening Kenn Borek Air, a Canadian airline IATA code