Definition of "AU"

AU

adjective
not comparable
1. (numismatics) Initialism of almost uncirculated.
noun
plural AUs
1. (medicine, dermatology) Initialism of alopecia universalis.
2. (astronomy) Initialism of astronomical unit.
  Quotations
  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.
  2008, BioWare, Mass Effect, Redwood City: Electronic Arts, PC, scene: Tuntau
3. Initialism of angstrom unit.
4. (fandom slang) Initialism of alternate universe.
5. Initialism of arbitrary unit.
proper noun
1. Initialism of African Union.