What does KOS stand for?

Kent University On-Line System - Computer science (PDAA)

Knights of Shadow

Konkomba - Language code (ETLW)

Kosick Corporation, Fox Lake, IL - Manufacturer code for watercraft hull identification number (USCG)

Kosmodemyansk - Former USSR - Seismograph station code, US Geological Survey - Closed (SEIS)

Kosovaair - Yugoslavia - ICAO designator (FAAC)