Longest-serving U.S. first lady, informally
![Ross](/clue/static/ross-mug.min.png)
I believe the answer is:
eleanor
(Other definitions for eleanor that I've seen before include "Near Leo (anag) - girl's name" , "- - Rigby: Beatles song" , "Franklin D. Roosevelt's wife" , "- of Aquitaine, - of Castile (queens)" , "Wife of F. D. Roosevelt" .)