Ha may refer to:

Agencies and organizations

Health authority Between 1996 and 2002 the English National Health Service was organised under the following health authorities. In 2002 the health authorities were reorganised and their boundaries changed to constitute 28 strategic health authorities, which were ...

Hells Angels Motorcycle Club The Hells Angels Motorcycle Club (HAMC) is a worldwide outlaw motorcycle club whose members typically ride Harley-Davidson motorcycles. In the United States and Canada, the Hells Angels are incorporated as the Hells Angels Motorcycle Corporatio ...

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

Arts, entertainment, and media

* Ha (Doseone album), ''Ha'' (Doseone album), 2005 * Ha (Talvin Singh album), ''Ha'' (Talvin Singh album), 2002 * Ha! (Killing Joke album), ''Ha!'' (Killing Joke album), 1982 * Ha (song), "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 (He (letter)#Arabic hāʾ, hāʾ), ح (Heth#Arabic ḥāʾ, 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, 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 (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

Surnames

*Ha (Chinese surname) (wiktionary:哈, 哈), found in the ''Hundred Family Surnames'' *Ha (Korean surname) (wiktionary:하, 하, 河 or 夏) *Hà, Vietnamese surname *Hạ, Vietnamese surname *Xia (surname) (wiktionary:夏, 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