HSI may refer to: Science and technology Hardware Security Integration HSI color space, used in computer vision applications Heterosubtypic immunity High Speed Interconnect, a Nvidia computer chip Horizontal shaft impactor, a type of rock crusher Horizontal situation indicator, an aircraft instrument Hurricane Severity Index Hyperspectral imaging Other uses (surname), various Chinese surnames, romanized in Pinyin HSI (track team) Croatian Syrmian Initiative (), an ethnic-Croat political party in Serbia Hang Seng Index, a stock market index Hastings Municipal Airport, in Hastings, Nebraska, United States Hispanic-serving institution, an American college designation Homeland Security Investigations, U.S. federal law enforcement agency Horizon Services, an American rehabilitation clinic Humane Society International, nonprofit organization for animal welfare Icelandic Handball Association (, ) Horizontal situation indicator, (aircraft avionics) See also Xi (disambiguation) — and are different transliterations of the same sound in Chinese