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au

1 American  
[oh] / oʊ /
French.

plural

aux

  1. to the; at the; with the.

Au 2 American  

abbreviation

  1. author. Also au

Au 3 American  
Symbol, Chemistry.

  1. gold.

AU 4 American  

abbreviation

  1. astronomical unit.

A.U. 5 American  
Or a.u.

abbreviation

  1. angstrom unit.

Au 1 British  

symbol

  1. gold

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
AU 2 British  

abbreviation

  1. African Union

  2. Also: a.u..  angstrom unit

  3. Also: a.u..  astronomical unit

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
au 3 British  

abbreviation

  1. Australia

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
AU Scientific  

  1. Abbreviation of astronomical unit

Etymology

Origin of Au

From the Latin word aurum

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

But with some notable exceptions—Henri-Georges Clouzot’s “Diabolique,” Julien Duvivier’s “Panique” and Jacques Becker’s “Touchez pas au Grisbi” among them—much of this tradition remains unknown to American viewers.

From The Wall Street Journal • Jan. 21, 2026

Towers of onion rings stacked high, bone-in rib-eyes, bubbling pots of lobster mac and cheese, fries and meats drowning in au poivre.

From Los Angeles Times • Oct. 31, 2025

"Many homes have been washed away on the coast," said Pascal Bimenyimana from the Christian NGO, World Relief, in Port au Prince.

From BBC • Oct. 29, 2025

External link The company is also central to what is au courant: the credit cycle and the AI boom, and also as an investment opportunity itself—or not.

From Barron's • Oct. 24, 2025

She pours me café au lait—mixing the milk from the pot with coffee in my cup.

From "Ninth Ward" by Jewell Parker Rhodes

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.