HL
HL may refer to: == In arts and entertainment == Half-Life (series), a video game series by Valve Half-Life (video game), the first game in that series Horseland, an online community and virtual game Harry Styles and Louis Tomlinson, part of the popular boyband One Direction known as HL when referred to together == Businesses == Hangars Liquides, an electronic music label Hargreaves Lansdown, a British investment company Hitachi-LG Data Storage, an optical disc drive manufacturer Hogan Lovells, an international law firm Houlihan Lokey, an international investment bank Hovedstadens Lokalbaner, a Danish local railway company HL Group, a South Korean company == In linguistics == ⟨hl⟩, a Latin-script digraph Reduction of /hl/ to /l/ in Old/Middle English Voiceless alveolar lateral fricative, a sound sometimes represented as ⟨hl⟩ == Science, technology, and mathematics == HL gas, a mixture of sulfur mustard and lewisite Half-life, in nuclear physics Hectolitre, a unit of volume Hessdalen light, an unexplained light seen in Norway Hodgkin's lymphoma, a highly treatable hematological malignancy ("blood cancer") Hotline, a telecommunications link Hydrogen line, a spectral line Hypotenuse Leg, a postulate of geometry HL, an amateur radio call sign prefix in South Korea == Other uses == Croatian Labourists – Labour Party (Croatian: Hrvatski laburisti - Stranka rada), a political party in Croatia Headline, a text indicating the nature of the article below it Heilongjiang, a province of China (Guobiao abbreviation HL) Higher Level, a level of course difficulty in the International Baccalaureate Diploma Programme Hit list (disambiguation) HL v United Kingdom a law case at the European Court of Human Rights, sometimes known as the HL case.