H1, H-1, H01, H I may refer to:

Places

Interstate H-1 Interstate H-1 (H-1) is the longest (27.16 miles = 43.71km) and busiest Interstate Highway in the US state of Hawaii. The highway is located on the island of Oʻahu. Despite the number, this is an east–west highway; the 'H'-series (for H ...

, a highway in Hawaii * Area H1, the area of Hebron controlled by the Palestinian Authority under the Hebron Protocol

Science

* H1 (particle detector) *

Histamine H1 receptor The H1 receptor is a histamine receptor belonging to the family of rhodopsin-like G-protein-coupled receptors. This receptor is activated by the biogenic amine histamine. It is expressed in smooth muscles, on vascular endothelial cells, in ...

Histone H1 Histone H1 is one of the five main histone protein families which are components of chromatin in eukaryotic cells. Though highly conserved, it is nevertheless the most variable histone in sequence across species. Structure Metazoan H1 prote ...

, a protein * British NVC community H1, a heath zone *

Hydrogen atom A hydrogen atom is an atom of the chemical element hydrogen. The electrically neutral hydrogen atom contains a single positively charged proton in the nucleus, and a single negatively charged electron bound to the nucleus by the Coulomb for ...

(H₁) *

Protium (isotope) Hydrogen (H) has three naturally occurring isotopes: H, H, and H. H and H are stable, while H has a half-life of years. Heavier isotopes also exist; all are synthetic and have a half-life of less than 1 zeptosecond (10 s). Of these, H is ...

, an isotope of hydrogen *

H I region An HI region or H I region (read ''H one'') is a cloud in the interstellar medium composed of neutral atomic hydrogen (HI), in addition to the local abundance of helium and other elements. (H is the chemical symbol for hydrogen, and "I" is the Ro ...

, a cloud in the interstellar medium * ATC code H01 ''Pituitary and hypothalamic hormones and analogues'', a subgroup of the Anatomical Therapeutic Chemical Classification System * Haplogroup H1 (disambiguation), a grouping in genetics based on certain similarities *

Alternative hypothesis In statistical hypothesis testing, the alternative hypothesis is one of the proposed propositions in the hypothesis test. In general the goal of hypothesis test is to demonstrate that in the given condition, there is sufficient evidence supporting ...

(H₁)

Technology

* , level 1 heading markup for HTML Web pages; see

HTML element An HTML element is a type of HTML (HyperText Markup Language) document component, one of several types of HTML nodes (there are also text nodes, comment nodes and others). The first used version of HTML was written by Tim Berners-Lee in 199 ...

* DSC-H1, a Sony Cybershot digital camera * H1, John Harrison's first marine chronometer *

Tianwen-1 -1 ( zh , s = 天问一号) (also referred to as TW-1) is an interplanetary mission by the China National Space Administration (CNSA) which sent a robotic spacecraft to Mars, consisting of 6 spacecraft: an orbiter, two deployable cameras, lan ...

(formerly ''Huoxing-1''), first Chinese space probe to reach Mars * H-1NF, the Australian Plasma Fusion Research Facility, formerly H-1 Heliac stellarator

Transportation

* H1 Lamp, an automotive halogen light bulb * H-I or H–1, a Japanese rocket *

Rocketdyne H-1 The Rocketdyne H-1 was a thrust liquid-propellant rocket engine burning LOX and RP-1. The H-1 was developed for use in the S-I and S-IB first stages of the Saturn I (rocket), Saturn I and Saturn IB rockets, respectively, where it was used in c ...

, a liquid-propellant rocket engine

Aviation

* Bell Huey family Bell H-1, series of helicopters with that designation * Hooters Air airline *

Hughes H-1 Racer The Hughes H-1 Racer is a racing aircraft built by Hughes Aircraft in 1935. Using different wings, it set both a world airspeed record and a transcontinental speed record across the United States. The H-1 Racer was the last aircraft built by a p ...

, a racing aircraft

Motor vehicles

* Haval H1, a Chinese subcompact crossover *

Hummer H1 The Hummer H1 is a full-size four-wheel-drive utility vehicle based on the M998 Humvee, which was developed by AM General when it was a subsidiary of American Motors Corporation (AMC). Originally designed strictly for military use, the off-r ...

, an American full-size SUV *

Hyundai H-1 Hyundai H-1 is a nameplate of a van and pickup truck used by Hyundai Motor Company in European export markets for three related models: * Hyundai Starex, (called i800 in Europe, iLoad in Australia and H-200 in the Netherlands) a minibus/van * Hyun ...

, a South Korean commercial van * Tiger H1, a German heavy tank used during WW2

Motorcycles

* Kawasaki H1 Mach III, road motorcycle * Kawasaki H1R, racing motorcycle

Ships

* HMS ''H1'', a 1915 British Royal Navy H-class submarine * HMS ''Hotspur'' (H01), a 1935 British Royal Navy H-class destroyer * USS ''H-1'', a 1913 United States Navy submarine

Rail

* LB&SCR H1 class, a class of British steam locomotives * LNER Class H1, a class of British steam locomotives *Designation for

METRORail METRORail is the light rail system in Houston, Texas (United States). In , the system had a ridership of , or about per weekday as of . METRORail ranks as the second most-traveled light rail system in the Southern United States and the List ...

Siemens S70 light rail vehicles

Time

*H1 may refer to the first half of the business year, while H2 refers to the second half.

Other uses

* H1 (classification), a para-cycling classification * , one of the three laryngeals in the reconstructed Proto-Indo-European language *

H1 Unlimited H1 Unlimited is an American unlimited hydroplane racing league that is sanctioned by the American Power Boat Association (APBA). Until 2009, the series was known as ABRA Unlimited Hydroplane, in turn renamed from APBA Unlimited Hydroplane in 2004. ...

, a premier unlimited hydroplane racing league *'' Hora Um da Notícia'', a news program aired by Rede Globo