What does HUK stand for?

Hulung - Language code (ETLW)

Human Urinary Kallikrein - Medicine (DMAA)

Hungarian-Ukranian Heavy Lift Ltd. - Hungary - ICAO designator (FAAC)

Hunter-Killer - Operations against submarines - Navy

Matrix Marine, Ventura, CA - Manufacturer code for watercraft hull identification number (USCG)