who's who

noun6

1. •
   A publication containing biographies of well-known or important people.

   • Nearly every country has now a Who's Who, which gives a brief outline of the life and work of living men who have distinguished themselves in various ways. — 1914
2. •
   A list of notable, famous, or upper-class people.

   • In the growing who's who of Negro educators, the name of Cleo W. Blackburn, 45, ranks high. — 1954
3. •
   Collectively, the elite class.
4. •
   The identities of specific people, understood in terms of such distinguishing characteristics as their backgrounds, prominence, achievements, jobs, etc., as a basis for comparing them and especially as a basis for ranking them within a social group.

   • Mrs. Falconer cannot well avoid asking you to some of her entertainments, and it will be pleasant to you to know who's who beforehand. — 1814
5. •
   A person appearing in a Who's Who publication.

   • Sixty-one From Wisconsin Make Debut as Who's Whos [headline]: — 1942
6. •
   A celebrity or famous person, someone likely to be in such a publication.