H3, H03 or H-3 may refer to:

Entertainment

* '' Happy Hustle High'', a manga series by Rie Takada, originally titled "H3 School!" * ''H3'' (film), a 2001 film about the 1981 Irish hunger strike * h3h3Productions, styled " 3, a satirical YouTube channel

Science

Triatomic hydrogen Triatomic hydrogen or H3 is an unstable triatomic molecule containing only hydrogen. Since this molecule contains only three atoms of hydrogen it is the simplest triatomic molecule and it is relatively simple to numerically solve the quantum mechan ...

(H₃), an unstable molecule * Trihydrogen cation (H₃⁺), one of the most abundant ions in the universe * Tritium (Hydrogen-3, or H-3), an isotope of hydrogen *

ATC code H03 H03A Thyroid preparations H03AA Thyroid hormones :H03AA01 Levothyroxine sodium :H03AA02 Liothyronine sodium :H03AA03 Combinations of levothyroxine and liothyronine :H03AA04 Tiratricol :H03AA05 Thyroid gland preparations H03B Antithyroid pre ...

''Thyroid therapy'', a subgroup of the Anatomical Therapeutic Chemical Classification System *

British NVC community H3 NVC community H3 (''Ulex minor - Agrostis curtisii'' heath) is one of the heath communities in the British National Vegetation Classification system. It is one of three communities which are considered transitional between the lowland dry heaths a ...

, a heath community of the British National Vegetation Classification system * Histamine H₃ receptor, a human gene *

Histone H3 Histone H3 is one of the five main histones involved in the structure of chromatin in eukaryotic cells. Featuring a main globular domain and a long N-terminal tail, H3 is involved with the structure of the nucleosomes of the 'beads on a stri ...

, a component of DNA higher structure in eukaryotic cells * , one of the three laryngeals in the reconstructed Proto-Indo-European language *

Hekla 3 eruption The Hekla 3 eruption (H-3) circa 1000 BC is considered the most severe eruption of Hekla during the Holocene. It threw about 7.3 km3 of volcanic rock into the atmosphere, placing its Volcanic Explosivity Index (VEI) at 5. This would have ca ...

, a huge volcanic eruption around 1000 BC

Computing

* , the level-3 HTML heading markup element *

HTTP/3 HTTP/3 is the third major version of the Hypertext Transfer Protocol used to exchange information on the World Wide Web, complementing the widely-deployed HTTP/1.1 and HTTP/2. Unlike previous versions which relied on the well-established TCP ( ...

, the third revision of a protocol for the World Wide Web * Socket H3, the common name of the

LGA 1150 LGA 1150, also known as Socket H3, is a zero insertion force flip-chip land grid array (LGA) CPU socket designed by Intel for CPUs built on the Haswell microarchitecture. This socket is also used by the Haswell's successor, Broadwe ...

CPU socket

Transportation

Air and space

* H3 (rocket), an expendable launch system under development by Japan Aerospace Exploration Agency * Harbour Air Seaplanes (IATA code), a Canadian charter airline *

H-3 Air Base H-3 Air Base (code-named 202C, 202D) is part of a cluster of former Iraqi Air Force bases in the Al-Anbar Governorate of Iraq. H3 is located in a remote stretch of Iraq's western desert, about 435 kilometers from Baghdad in western Iraq. It is cl ...

, former Iraqi Air Force base in western Iraq *

H-3 Sea King The Sikorsky SH-3 Sea King (company designation S-61) is an American twin-engined anti-submarine warfare (ASW) helicopter designed and built by Sikorsky Aircraft. A landmark design, it was one of the first ASW rotorcraft to use turboshaft engin ...

, a United States Navy helicopter *

Standard H-3 The Standard H-2 was an early United States, American United States Army Air Corps, Army reconnaissance aircraft, ordered in 1916 in aviation, 1916. The H-2 was built by the Standard Aircraft Corporation, and previously known as the Sloane H-2. I ...

, an improved version of the 1916 Standard H-2 aircraft

Automobiles

Brilliance H3 The Brilliance H3 sedan is a compact car produced by Brilliance Auto aimed to replace the Brilliance H330 The Brilliance H330 sedan and Brilliance H320 hatchback duo are compact cars ( C) produced by Brilliance Auto aimed to replace the Brillia ...

, a Chinese compact sedan * Haval H3, a Chinese compact SUV *

Huansu H3 The Huansu H3 is a 7-seat MPV produced by Huansu, a brand of the Chonqing Bisu Automotive Corporation, which is closely related to Beiqi-Yinxiang, a joint venture between Beijing Auto (Beiqi) and the Yinxiang Group The Yinxiang Group (银翔 ...

, a Chinese compact MPV * Hummer H3, an American mid-size SUV

Ships

* USS ''H-3'' (SS-30), a 1914 United States Navy H-class submarine * HMS ''Grenville'' (H03), a 1935 British Royal Navy destroyer * HMS ''H3'', a 1915 British Royal Navy H-class submarine

Rail

* H3 series of METRORail tramways in Houston

Roads

* H3 Monks Way, a road part of the Milton Keynes grid road system, United Kingdom *

Interstate H-3 Interstate H-3 (abbreviated H-3) is an Interstate Highway located entirely within the U.S. state of Hawaii on the island of Oahu. H-3 is also known as the John A. Burns Freeway. It crosses the Ko'olau Range along several viaducts and through th ...

, a highway in Hawaii

Other uses

* H3 (classification), a para-cycling classification * H3, an 18th-century marine chronometer by

John Harrison John Harrison ( – 24 March 1776) was a self-educated English Carpentry, carpenter and clockmaker who invented the marine chronometer, a long-sought-after device for solving the History of longitude, problem of calculating longitude while at s ...

* H3, a type of automotive halogen lamp * H3 (pyrotechnics), a pyrotechnic composition * H3 Hardy Collaboration Architecture, a firm started by

Hugh Hardy Hugh Hardy (July 26, 1932 – March 17, 2017) was an American architect, known for designing and revitalizing theaters, performing arts venues, public spaces, and cultural facilities across the United States. ''The New Yorker'' writer Brendan ...

* H3 Pharmaceutical Chemistry, an advanced subject for GCE A-level students in Singapore * DSC-H3, a 2008

Sony Cyber-shot Cyber-shot is Sony's line of point-and-shoot digital cameras introduced in 1996. Cyber-shot model names use a DSC prefix, which is an initialism for "Digital Still Camera". Many Cyber-shot models feature Carl Zeiss trademarked lenses, while othe ...

camera * Hash House Harriers, an international group of non-competitive running, social and drinking clubs *

H3 (Kuwait) H3 (also H3, as-Sabiyah) is an archaeological site in the Subiya Region (Kuwait) that was occupied during the second half of the sixth millennium BC. It was a cultural borderland between Neolithic Arabia and Mesopotamia. Among the finds at the s ...

, an archaeological site