What does KIU stand for?

Gikuyu - Language code (ETLW)

Kainantu - New Guinea - Airport symbol (AD)

Kallikrein Inactivator Unit - Analytical biochemistry

Kallikrein-Inhibiting Unit - Analytical biochemistry (DAVI)

Kirby Craft Boats, Bloomington, TX - Manufacturer code for watercraft hull identification number (USCG)

Krein Inactivator Unit (DB)