Ha may refer to:

Agencies and organizations

Health authority Between 1996 and 2002, the National Health Service in England and Wales was organised under health authorities (HAs). There were 95 HAs at the time of their abolition in England in 2002, and they reported to the eight regional offices of the NHS ...

, a former type of administrative organisation of the NHS in England and Wales *

Hells Angels Motorcycle Club The Hells Angels Motorcycle Club (HAMC) is an international outlaw motorcycle club founded in California whose members typically ride Harley-Davidson motorcycles. In the United States and Canada, the Hells Angels are incorporated as the Hells ...

Highways Agency National Highways (NH), formerly Highways England and before that the Highways Agency, is a government-owned company charged with operating, maintaining and improving motorways and major A roads in England. It also sets highways standards u ...

(renamed ''Highways England'', now ''National Highways''), UK government body maintaining England's major roads * Homelessness Australia, peak body organisation for homeless people and services * Homosexuals Anonymous an ex-gay program for dealing with unwanted same-sex attractions * Hong Kong Housing Authority

Arts, entertainment, and media

* ''Ha'' (Doseone album), 2005 * ''Ha'' (Talvin Singh album), 2002 * ''Ha!'' (Killing Joke album), 1982 * "Ha" (song), by Juvenile * Ha! (TV channel), an American all-comedy TV channel * '' Hamar Arbeiderblad'', a Norwegian newspaper * '' Human Action'', a book by the Austrian economist Ludwig von Mises * The Jim Henson Company, formerly known as ha!

Language

* Ha (Javanese) (ꦲ), a letter in the Javanese script * Ha (kana), in syllabic Japanese script *ه ( hāʾ), ح (

ḥāʾ Heth, sometimes written Chet or Ḥet, is the eighth letter of the Semitic abjads, including Phoenician ''ḥēt'' 𐤇, Hebrew ''ḥēt'' , Aramaic ''ḥēṯ'' 𐡇, Syriac ''ḥēṯ'' ܚ, and Arabic ''ḥāʾ'' . It is also related to t ...

), or خ (

ḫāʾ , , or Xe (, transliterated as ( DIN-31635), ( Hans Wehr), (ALA-LC) or (ISO 233)) is one of the six letters the Arabic alphabet added to the twenty-two inherited from the Phoenician alphabet (the others being , , , , ). It is based on the ...

), Arabic letters * Ha language, the language of the Ha people in eastern Africa *

Hausa language Hausa (; / ; Hausa Ajami, Ajami: ) is a Chadic language spoken primarily by the Hausa people in the northern parts of Nigeria, Ghana, Cameroon, Benin and Togo, and the southern parts of Niger, and Chad, with significant minorities in Ivory Coas ...

, ISO 639-1 code HA

Places

* Ha, Bhutan * Hå, Norway * Ha Gorge, Greece * HA postcode area, a group of English postal districts in north-west London *

Henan Henan; alternatively Honan is a province in Central China. Henan is home to many heritage sites, including Yinxu, the ruins of the final capital of the Shang dynasty () and the Shaolin Temple. Four of the historical capitals of China, Lu ...

, a province of China (Guobiao abbreviation HA)

Science and technology

Chemistry

* Hahnium, an element now called Dubnium * Hyaluronan (Hyaluronic acid), a carbohydrate structure *

Hydroxylapatite Hydroxyapatite ( IMA name: hydroxylapatite) (Hap, HAp, or HA) is a naturally occurring mineral form of calcium apatite with the formula , often written to denote that the crystal unit cell comprises two entities. It is the hydroxyl endmembe ...

, a mineral

Medicine

* Hyperandrogenic anovulation, also called polycystic ovary syndrome * Health anxiety (HA) or

hypochondriasis Hypochondriasis or hypochondria is a condition in which a person is excessively and unduly worried about having a serious illness. Hypochondria is an old concept whose meaning has repeatedly changed over its lifespan. It has been claimed that th ...

(hypochondria) *

Hemagglutinin (influenza) Influenza hemagglutinin (HA) or haemagglutinin#Notes, (British English) is a homotrimeric glycoprotein found on the surface of influenza viruses and is integral to its infectivity. Hemagglutinin is a class I fusion protein, having multifunc ...

(HA), an antigenic glycoprotein from Influenza viruses * Hemagglutination assay, a measurement of viruses or bacteria

Units of measure

Hartree The hartree (symbol: ''E''h), also known as the Hartree energy, is the measurement unit, unit of energy in the atomic units system, named after the British physicist Douglas Hartree. Its CODATA recommended value is = The hartree is approximat ...

, an atomic unit of energy *

Hectare The hectare (; SI symbol: ha) is a non-SI metric unit of area equal to a square with 100-metre sides (1 hm2), that is, square metres (), and is primarily used in the measurement of land. There are 100 hectares in one square kilometre. ...

(ha), a unit of area * Hectoampere, a unit of electric current

Other uses in science and technology

* ha (function prefix) (half), a prefix for some trigonometric functions in mathematics *

High availability High availability (HA) is a characteristic of a system that aims to ensure an agreed level of operational performance, usually uptime, for a higher than normal period. There is now more dependence on these systems as a result of modernization ...

, systems design and implementation with a view to maximising service *

Hour angle In astronomy and celestial navigation, the hour angle is the dihedral angle between the '' meridian plane'' (containing Earth's axis and the zenith) and the '' hour circle'' (containing Earth's axis and a given point of interest). It may be ...

, in astronomy, one of the coordinates of the equatorial coordinate system * H_a, or

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 ...

, in statistical testing *

H-alpha Hydrogen-alpha, typically shortened to H-alpha or Hα, is a deep-red visible spectral line of the hydrogen atom with a wavelength of 656.28 nm in air and 656.46 nm in vacuum. It is the first spectral line in the Balmer series and is em ...

(Hα), a deep-red visible spectral line of the hydrogen atom

Surnames

* Ha (Chinese surname) ( 哈), found in the ''

Hundred Family Surnames The ''Hundred Family Surnames'' (), commonly known as ''Bai Jia Xing'', also translated as ''Hundreds of Chinese Surnames'', is a classic Chinese language , Chinese text composed of common Chinese surnames. An unknown author compiled the book ...

'' * Ha (Korean surname) (, 河 or 夏) * Hà, Vietnamese surname *

Xia (surname) Xia is the Standard Chinese, Mandarin pinyin romanization of the Chinese surname written in Chinese character. It is romanized Hsia in Wade–Giles, and Ha in Cantonese. Xia is the 154th surname in the Song dynasty Chinese classics, classic text ' ...

( 夏), romanized as Ha in Cantonese, Korean and Vietnamese pronunciation

Transportation

* British Rail Class 71, a locomotive (classified type HA under the Southern Region's pre-TOPS scheme) *

Hawaiian Airlines Hawaiian Airlines, Inc. ( ) is a commercial U.S. airline headquartered in Honolulu, and a subsidiary of the Alaska Air Group. It is the largest operator of commercial flights to and from the island state of Hawaiʻi, and the tenth largest ...

(IATA designator HA) *

(now ''National Highways''), UK government body maintaining England's major roads

Other uses

* Ha (mythology) * Ha, one of deities

Heng and Ha Heng and Ha () are two generals of the Shang dynasty in Chinese mythology, featured within the 16th-century Chinese fantasy novel ''Investiture of the Gods''. These two fictional characters were created by the author of ''Investiture of the Gods'' ...

* Ha people, a Tanzanian people * Hospitalman Apprentice, a U.S. Navy rank