AU

See also: Appendix:Variations of "au"

㍳ U+3373, ㍳ SQUARE AU ← ㍲ [U+3372] CJK Compatibility ㍴ → [U+3374]

Translingual

Etymology 1

Symbol

AU

1. (international standards) ISO 3166-1 alpha-2 country code for Australia.

   Synonym: AUS (alpha-3)

Usage notes

• The code includes the Ashmore and Cartier Islands and the Coral Sea Islands.

Etymology 2

Symbol

AU

1. astronomical unit

Usage notes

• Though "AU" is in frequent use by professional bodies and the public, the unit symbol au is recommended by the IAU and ua by the BIPM.

Synonyms

• au (IAU recommended unit symbol for astronomical units)
• ua (BIPM recommended unit symbol for astronomical units)
• ㍳ (Unicode glyph for astronomical unit)

Anagrams

• UA

English

Alternative forms

• a.u., A.U., A. U.

Adjective

AU (not comparable)

1. (numismatics) Initialism of almost uncirculated.

Translations

almost uncirculated

• French: SPL (fr)

Noun

AU (countable and uncountable, plural AUs)

1. (medicine, dermatology) Initialism of alopecia universalis.
2. (astronomy, metrology) Initialism of astronomical unit.
   • 2008, BioWare, Mass Effect, Redwood City: Electronic Arts, →ISBN, →OCLC, PC, scene: Tuntau:

     Tuntau is an enormous, low-density terrestrial planet, with a thick atmosphere of methane and helium. Despite being nearly 20 AU from Phoenix, the star's great heat and the insulating thickness of the atmosphere make the surface surprisingly temperate.

3. (physics, metrology) Initialism of angstrom unit.
4. (fandom slang) Initialism of alternate universe or alternative universe.
5. Initialism of arbitrary unit.
6. Initialism of animal unit.

Proper noun

AU

1. Initialism of African Union.
   • 2026 September 4, Thomas Mukhwana, Wycliffe Muia, “UN votes to adopt new world map to reflect Africa's true size”, in BBC News, retrieved 4 September 2026:

     The "Correct the Map" resolution, sponsored by Togo and backed by African Union (AU) members, passed with the support of 164 nations, including France and the UK.

2. Initialism of Age of Ultron.

See also

• AUKUS

Anagrams

• U/A, UA, uA

Indonesian

Pronunciation

• IPA^(key): /ˈa.u/, [ˈa.u]

Noun

AU (plural AU-AU)

1. initialism of angkatan udara (“air force”)
2. (fandom slang) initialism of alternate universe (“fan fiction published on microblogging sites”)