Phrase for the elder of my younger sisters?

"Mamie is my next-younger sister; Sally is the baby.


You can call your younger sibling, who's older than her smaller sister, the second-youngest sister.

closeness to my littlest sister. Since I was her big brother, she thought I was the greatest thing. When my second-youngest sister, Pat, was born, I was ten or eleven, so the last thing I wanted to be doing was holding and cuddling a baby.