H2

H2, H02, or H-2 may refer to:

Arts and media

 * Armenia 2 (H2), a private television company broadcasting in Armenia and Nagorno-Karabakh
 * H2 (A&E Networks), the rebranded name of the former channel History International
 * H2 (American TV channel), the American version of the channel
 * H2 (manga), a baseball manga by Mitsuru Adachi
 * Halo 2, a video game for the Xbox, created and developed by Bungie
 * Halloween II (2009 film), initially abbreviated to H2
 * Hollywood Squares, referred to as H2 informally during the 2002–2004 seasons

Computing

 * , level 2 heading markup for HTML Web pages, see HTML element
 * H2 (database), an open-source Java SQL database-management system
 * DSC-H2, a 2006 Sony Cyber-shot H series camera
 * HTTP/2, major revision of HTTP, often abbreviated in discussions as h2, and identifying itself to other servers as h2 in TLS negotiation or h2c in the HTTP Upgrade header
 * LGA 1155 CPU socket, also known as Socket H2

Roads and transportation

 * Interstate H-2, a highway in Hawaii, located on the island of Oahu
 * London Buses route H2

Biology and medicine

 * ATC code H02 Corticosteroids for systemic use, a subgroup of the Anatomical Therapeutic Chemical Classification System
 * British NVC community H2, a heath community in the British National Vegetation Classification system
 * Histamine H2 receptor
 * Prostaglandin H2
 * H-2, the Major histocompatibility complex of the mouse (equivalent of the Human Leukocyte Antigens)
 * $$H^2$$ or $$h^2$$, wide- or narrow-sense heritability

Chemistry

 * H2, the chemical formula for hydrogen gas (dihydrogen)
 * Deuterium (Hydrogen-2, H-2, 2H), the isotope of hydrogen with one proton, one neutron, and one electron

Other uses in science and mathematics

 * H II region, a region of interstellar atomic hydrogen that is ionized
 * *h2, one of the three laryngeals in the reconstructed Proto-Indo-European language
 * The Hardy space H2

Air and space

 * H-II, a family of Japanese liquid-fueled rockets
 * H-IIA
 * H-IIB
 * H-II Transfer Vehicle, a Japan Aerospace Exploration Agency uncrewed spacecraft
 * H-2 MUPSOW, a precision-guided glide bomb manufactured by Pakistan
 * Landgraf H-2, an American single-seat twin-rotor helicopter produced in 1944
 * Standard H-2, a U.S. Army reconnaissance plane produced in 1916

Automobiles

 * Haval H2, a Chinese subcompact SUV
 * Hummer H2, an American full-size SUV

Motorcycles

 * Kawasaki H2 Mach IV, 1970s two-stroke motorcycle
 * Kawasaki Ninja H2, 2010s supercharged motorcycle

Rail

 * LB&SCR H2 class, a British LB&SCR locomotive
 * GNR Class H2, a class of British steam locomotives
 * LNER Class H2, a class of British steam locomotives
 * H02 locomotive (Germany), a high-pressure steam locomotive made in 1930
 * Saxon XII H2, a German steam locomotive produced in 1922
 * PRR H2, a model within the American PRR locomotive classification
 * H2, designation for METRORail Siemens S70 light rail vehicles

Sea

 * HMAS Success (H02), a Royal Australian Navy Admiralty S-class destroyer completed in 1918
 * HMS Exmouth (H02), a British Royal Navy E-class destroyer commissioned in 1934
 * HMS H2, a British Royal Navy H class submarine commissioned in 1915
 * USS H-2 (SS-29), a U.S. Navy H-class submarine commissioned in 1913

Other uses

 * H-2 Air Base, a military air base in Iraq
 * H2 (classification), a para-cycling classification
 * H-2A Visa, a United States visa for temporary or seasonal agricultural work
 * H2, the second half of the business year
 * H2 lamp, a halogen vehicle headlamp no longer manufactured
 * H2, a model of hurricane tie manufactured by Simpson Strong-Tie Co.
 * Sky Airline (IATA code H2)
 * Area H2, an Israeli-controlled area under the Hebron Protocol
 * H2 as the nickname for New Zealand civil servant Heather Simpson