HN or Hn may refer to:
Arts and entertainment French horn (musical score notation: Hn.) HN, a numbering system for Royal Doulton Figurines, e.g. HN211 Headline News, former name of the HLN TV network Hacker News, a social news website
Businesses and organizations Equair (former IATA code: HN), a former Ecuadorian airline HeavyLift Cargo Airlines (former IATA code: HN), a former Australian cargo airline Hutchinson and Northern Railway (reporting mark: HN), Kansas, US
Places Heilbronn (vehicle registration), a city in Germany Herceg Novi (car plates: HN), a town in Montenegro Honduras (ISO 3166-1 country code) Hunan, a province of China Thesprotia (vehicle plate code: ΗΝ), regional unit of Greece
Science and technology .hn, the Internet country code top-level domain (ccTLD) for Honduras Harmonic number, in mathematics
Other uses Hellenic Navy, the navy of Greece Hospitalman, a US Navy hospital corpsman rate , a two-letter combination used in some languages Reduction of /hn/ to /n/ in Old/Middle English
See also English horn (musical score notation: E. hn.) Saxhorn (musical score notation: S. hn.)