Ha

ha may mean:
*hectare (ha), SI (metric system) unit of surface area
*the ISO 639 alpha-2 language code for the widely-spoken African Hausa language

The all-uppercase HA may refer to:
*the Highways Agency, an executive agency, part of the Department for Transport in the United Kingdom
*the Ha! comedy channel, one of the precursors to Comedy Central
*the British Rail pre-TOPS classification for twenty-four electric locomotives, later known as British Rail Class 71
*Haiti (FIPS 10-4 country code)
*Hawaiian Airlines (IATA airline designator)
*Hearst-Argyle, a media company in the United States
*Hells Angels, a motorcycle club
*hemagglutinin or hemagglutination assay, in virology
*High availability
*Home agent, a computer router
*Home automation
*Homeowners association
*Hong Kong Housing Authority
*Hospital Authority, responsible for all public hospitals and institutes in Hong Kong
*Housing association
*HA postcode area, in Britain
*Hyaluronan, a molecule found in the body
*Hydroxylapatite, a mineral
*Head Automatica, an American powerpop band
* HA (video format)

Ha can mean:
*Ha (ethnic group), a people in Tanzania
* Hāʼ, a letter of Arabic alphabet (ﻩ)
*Kha, a letter of Cyrillic alphabet
*Ha (kana), romanisation of the Japanese kana は and ハ
*Ha, Bhutan
*Ha (mythology), a minor deity in Egyptian mythology
*the former symbol for the element dubnium (first called hahnium)
*Hå, a municipality in Norway
*"Ha" (song), a single by Juvenile

hA can mean:
*Hectoampere, an SI unit of electric current (equal to 100 A)

See also

*Haha, disambiguation