Ha may refer to:

Agencies and organizations

* Health authority * Hells Angels Motorcycle Club * Highways Agency (now ''National Highways''), UK government body maintaining England's major roads *

Homelessness Australia Homelessness Australia (HA) is the national peak body organisation for homelessness services and homeless people in Australia. The organisation provides systemic advocacy for the sector and works in collaboration with support services, state and n ...

, 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 The Hong Kong Housing Authority (HA) is the main provider of public housing in Hong Kong. It was established in April 1973 under the Housing Ordinance and is an agency of the Government of Hong Kong. In the same year, the Resettlement Departm ...

Highways Agency, or (HA), former name of Highways England, part of England's Department for Transport

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 ''Hamar Arbeiderblad'' (often referred to locally as "HA") is local newspaper published in Hamar, Norway by Hamar Media. The paper is edited by Carsten Bleness. HA was one of the first newspapers to place the internet edition of a newspaper behind ...

'', 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), or خ (

ḫāʾ or 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 (; /; Ajami: ) is a Chadic language spoken by the Hausa people in the northern half of Nigeria, Ghana, Cameroon, Benin and Togo, and the southern half of Niger, Chad and Sudan, with significant minorities in Ivory Coast. Hausa is a mem ...

, 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 (; or ; ; alternatively Honan) is a landlocked province of China, in the central part of the country. Henan is often referred to as Zhongyuan or Zhongzhou (), which literally means "central plain" or "midland", although the name is a ...

, a province of China (Guobiao abbreviation HA)

Science and technology

Chemistry

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

Medicine

* Hyperandrogenic anovulation, also called polycystic ovary syndrome * Health anxiety (HA) or hypochondriasis (hypochondria) * Hemagglutinin (influenza) (HA), an antigenic glycoprotein from Influenza viruses * Hemagglutination assay, a measurement of viruses or bacteria

Units of measure

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

, 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), or 10,000 m2, and is primarily used in the measurement of land. There are 100 hectares in one square kilometre. An acre i ...

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

Hour angle In astronomy and celestial navigation, the hour angle is the angle between two planes: one containing Earth's axis and the zenith (the '' meridian plane''), and the other containing Earth's axis and a given point of interest (the ''hour circle' ...

, 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 proposition 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

Surnames

* Ha (Chinese surname) ( 哈), found in the '' Hundred Family Surnames'' * Ha (Korean surname) ( 하, 河 or 夏) * Hà, Vietnamese surname * Hạ, Vietnamese surname * Xia (surname) ( 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 (IATA designator HA) * Highways Agency (now ''National Highways''), UK government body maintaining England's major roads

Other uses

Ha (mythology) Ha ( egy, ḥꜣ), in ancient Egyptian religion, was a god of the '' Western Desert & the fertile oasis of Western Desert of Egypt''. He was associated with the Duat (the underworld) and pictured as a man wearing the hieroglyph symbol for deser ...

* Ha, one of deities Heng and Ha *

Ha people __NOTOC__ The Ha, also called (''Waha'' in Swahili) or Abaha, are a Bantu ethnic group found in Kigoma Region in northwestern Tanzania bordering Lake Tanganyika.

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