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.
Postscript
Added on September 26, 2022
From The Constitution of Knowledge:
Rush Limbaugh, the doyen of conservative talk radio…
Postscript
Added on April 12, 2023
From Kingmakers:
Egypt’s policies were really inspired by the Envoy of a foreign state, who in theory is only one – and not even the doyen – of a large number of such Envoys…