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 * Highways Agency (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), or خ ( ḫāʾ), Arabic letters * Ha language, the language of the Ha people in eastern Africa * Hausa language, 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, 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, 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, systems design and implementation with a view to maximising service * Hour angle, in astronomy, one of the coordinates of the equatorial coordinate system * H_a, or alternative hypothesis, in statistical testing * H-alpha (Hα), a deep-red visible spectral line of the hydrogen atom

Surnames

* Ha (Chinese surname) ( 哈), found in the '' Hundred Family Surnames'' * Ha (Korean surname) (, 河 or 夏) * Hà, 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, one of deities Heng and Ha * Ha people, a Tanzanian people * Hospitalman Apprentice, a U.S. Navy rank