H4, H04, or H-4 may refer to:

Science and mathematics

* ATC code H04 ''Pancreatic hormones'', a subgroup of the Anatomical Therapeutic Chemical Classification System * Histamine H₄ receptor, a human gene *

Histone H4 Histone H4 is one of the five main histone proteins involved in the structure of chromatin in eukaryote, eukaryotic cells. Featuring a main globular domain and a long N-terminus, N-terminal tail, H4 is involved with the structure of the nucleos ...

, a protein involved in the structure of chromatin in eukaryotic cells *

Hydrogen-4 Hydrogen (1H) has three naturally occurring isotopes, sometimes denoted , , and . and are stable, while has a half-life of years. Heavier isotopes also exist, all of which are synthetic and have a half-life of less than one zeptosecond (10� ...

(H-4), an isotope of hydrogen * H₄, a

symmetry group In group theory, the symmetry group of a geometric object is the group of all transformations under which the object is invariant, endowed with the group operation of composition. Such a transformation is an invertible mapping of the ambient ...

in the fifth dimension.

Technology

H-4 SOW The H-4 SOW (Stand-Off Weapon) is a precision-guided glide bomb manufactured by NESCOM and deployed by the Pakistan Air Force, capable of striking targets at stand-off range. It has a terminal guidance system based on an infrared homing seeker, ...

, a precision-guided glide bomb used by the Pakistan Air Force *

Halo 4 ''Halo 4'' is a 2012 first-person shooter video game developed by 343 Industries and published by Microsoft Studios for the Xbox 360 video game console. ''Halo 4''s story follows a cybernetically enhanced human supersoldier, Master Chief, and ...

, a video game created by

343 Industries 343 Industries is an American video game developer located in Redmond, Washington, part of Xbox Game Studios. Headed by Pierre Hintze, the studio is responsible for the ''Halo'' series of military science fiction games, originally created and ...

for the

Xbox 360 The Xbox 360 is a home video game console developed by Microsoft. As the successor to the original Xbox, it is the second console in the Xbox series. It competed with Sony's PlayStation 3 and Nintendo's Wii as part of the seventh generation ...

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

, an 18th-century marine chronometer designed by John Harrison *

Zoom H4 Handy Recorder The H4 Handy Recorder is a handheld digital audio recorder from Zoom, featuring built-in condenser microphones in an X-Y stereo pattern, priced from around US$280 depending upon memory capacity . Recordings are stored on an SD card (128 MB ...

, a handheld digital audio recorder * , level 4 heading markup for HTML Web pages, see HTML element#heading

Transport

Automobiles and roads

* H4, a halogen

headlamp A headlamp is a lamp attached to the front of a vehicle to illuminate the road ahead. Headlamps are also often called headlights, but in the most precise usage, ''headlamp'' is the term for the device itself and ''headlight'' is the term for ...

bulb * H4, development name of the

Hummer HX The Hummer HX is a two-door off-road concept compact SUV that was revealed at the 2008 North American International Auto Show by General Motors. Design The objective of the HX concept car project was to potentially market a Hummer branded vehic ...

concept car * H-4, shorthand for a 4-cylinder horizontally-opposed or "flat four" engine (not to be confused with an actual

H engine An H engine is a piston engine comprising two separate flat engines (complete with separate crankshafts), most often geared to a common output shaft. The name "H engine" is due to the engine blocks resembling a letter "H" when viewed from the fr ...

) *

H4 Dansteed Way The Milton Keynes grid road system is a network of predominantly national speed limit, fully landscaped routes that form the top layer of the street hierarchy for both private and public transport in Milton Keynes, Buckinghamshire. The system i ...

, a road in Milton Keynes, England

Aviation

GEN H-4 The GEN H-4 is a Japanese helicopter under development by GEN Corporation of Nagano. The aircraft is intended to be supplied as a kit for amateur construction.Bayerl, Robby; Martin Berkemeier; et al: ''World Directory of Leisure Aviation 2011 ...

, a Japanese helicopter design *

Hughes H-4 Hercules The Hughes H-4 Hercules (commonly known as the ''Spruce Goose''; registration NX37602) is a prototype strategic airlift flying boat designed and built by the Hughes Aircraft Company. Intended as a transatlantic flight transport for use duri ...

(Spruce Goose), the largest flying boat ever built * H4, IATA code for Héli Sécurité Helicopter Airlines, based in France * H4, IATA code for

Inter Islands Airlines Inter Islands Airlines was an airline An airline is a company that provides air transport services for traveling passengers and freight. Airlines use aircraft to supply these services and may form partnerships or alliances with other ...

, based in Cape Verde

Ships and submarines

* HMS ''H4'', a 1915 British Royal Navy H-class submarine * HMS ''Tenedos'' (H04), a 1918 British Royal Navy Admiralty S-class destroyer * USS ''H-4'' (SS-147), a 1918 United States Navy submarine

Trains

GNR Class H4 The Great Northern Railway Class H4 (classified K3 by the LNER) was a class of 2-6-0 steam locomotive designed for mixed-traffic work. The type was a more powerful development of the earlier H3 ( LNER K2) class and was notable at the time, ...

, a 1920 British 2-6-0 steam locomotive model

Other uses

* ''H4'' (film), a 2013 film *

H-4 visa An H-4 visa is a United States visa issued to dependent family members of H-1B, H-1B1, H-2A, H-2B, and H-3 visa holders to allow them to travel to the United States to accompany or reunite with the principal visa holder. A dependent family mem ...

, issued by the U.S. Citizenship and Immigration Services * British NVC community H4, a heath community in the British National Vegetation Classification system *

H4 (classification) H4 is a para-cycling classification. The UCI recommends this be coded as MH4 or WH4. Definition Union Cycliste Internationale (UCI) defines H4 as: *Paraplegic with impairments corresponding to a complete lesion from Th11 or below * No lower limb ...

, a cycling classification used in para-cycling * H-4, a huge eruption of the

Hekla Hekla (), or Hecla, is a stratovolcano in the south of Iceland with a height of . Hekla is one of Iceland's most active volcanoes; over 20 eruptions have occurred in and around the volcano since 874. During the Middle Ages, the Icelandic Norse ...

volcano around 2310 BC * H4, Houston

Hash House Harriers The Hash House Harriers (HHH or H3) is an international group of non-competitive running social clubs. An event organized by a club is known as a Hash or Run, or a Hash Run. A common denominal verb for this activity is Hashing, with participan ...

, a social running club based in

Houston Houston (; ) is the most populous city in Texas, the most populous city in the Southern United States, the fourth-most populous city in the United States, and the sixth-most populous city in North America, with a population of 2,304,580 in ...

, Texas