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 (TV channel), the rebranded name of the former channel *History International*
* *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#heading
* H2 (DBMS), 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

## Science and mathematics
### Biology and medicine
* H02, a code for "Other inflammation of eyelid" in ICD-10 Chapter VII: Diseases of the eye, adnexa
* 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)
* Hydrogen-2, H-2, 2H (called deuterium), 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
* , one of the three laryngeals in the reconstructed Proto-Indo-European language
* The Hardy space H2

## Vehicles
### 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 unmanned 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 

### Rail
* LB&SCR H2 class, a British LB&SCR locomotive
* 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

### Road
* Hummer H2, a car model 
* Kawasaki H2 Mach IV, 1970s two-stroke motorcycle
* Kawasaki Ninja H2, 2010s supercharged motorcycle

### 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-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