who's who

American  

noun

1. a reference work containing short biographical entries on the outstanding persons in a country, industry, profession, etc..

   a who's who in automotive engineering.

2. the outstanding or influential persons in a community, industry, profession, or other group.

   The who's who of racing will be there.

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who's who British  

noun

1. a book or list containing the names and short biographies of famous people

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who's who Idioms  

1. The outstanding or best-known individuals of a group, as in Tonight's concert features a veritable who's who of musicians. This expression comes from the name of a famous reference work, Who's Who, first published in 1849, which contains biographical sketches of famous individuals and is regularly updated. Its name in turn was based on who is who, that is, the identity of each of a number of persons, a phrase dating from the late 1300s. [Early 1900s]

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Etymology

Origin of who's who

First recorded in 1840–50

Example Sentences

The moment flag football was approved for the 2028 Olympics in Los Angeles, a who’s who of the NFL’s biggest stars all had the same reaction: We want in.

From The Wall Street Journal

Kelly: We've also had a fair few people talk about being at your 40th birthday in January and it was like a who's who of football...

From BBC

It follows a year where he played host to a “who’s who” of American rivals, including Russian President Vladimir Putin, North Korean leader Kim Jong Un and leaders from Iran.

From The Wall Street Journal

“They’ve really got the who’s who list of customers that are buying the product. They’re having a lot of success against some very large legacy companies, like a Honeywell or a Safran, who have been incumbents in this space,” Reilly said.

From The Wall Street Journal

"He knows my players, he's well aware of who's who, and some of them still can't get their head around that when I tell them."

From Barron's