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

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

• Hueiyen Lanpao, a Meitei-English bilingual newspaper of Manipur
• 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)
• Hit list (disambiguation)
• House of Lords, the upper house of the Parliament of the United Kingdom
• Higher Level, a level of course difficulty in the International Baccalaureate Diploma Programme