Ha may refer to:
Agencies and organizations
- Health authority
- Hells Angels, a motorcycle gang
- 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
- Human Action, a book by the Austrian economist Ludwig von Mises
- The Jim Henson Company, formerly known as ha!
Languages and letters
- 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
Other uses in science and technology
- ha (function prefix) (half), a prefix for some trigonometric functions in mathematics
- Hartree, an atomic unit of energy
- Hectare (ha), a unit of area
- Hectoampere, a unit of electric current
- 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
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, or (HA), former name of Highways England, part of England's Department for Transport
Other uses
- Ha (mythology)
- Ha, one of deities Heng and Ha
- Ha people, a Tanzanian people
- Hospitalman Apprentice, a U.S. Navy rank
See also
- Haa (disambiguation)
- Haha (disambiguation)
- Has (disambiguation)