Doyenne

Definition: the eldest female in a group; a woman who is the senior member, as in age or rank, of a group, class, profession, etc.

This is the feminine version of the more rare “doyen,” which means:

the senior member of a body or group

a person considered to be knowledgeable or uniquely skilled as a result of long experience in some field of endeavor

“Doyen” is Old French for “dean” which vaguely means leader.

Why I Looked It Up

In a book about the Vanderbilt family, I found this caption:

Caroline Astor, the doyenne of Gilded Age New York society.