My brother is only 15 months older than me and they tried to get him to call me sister. He pronounced it "Sear." Some members of my family have called me that ever since.
Also, one great uncle gave every new member of the family (by birth or marriage) a nickname and he never called them by anything but their nickname. Mine was Frauline.
Oh... and when I was little (and sometimes still) my mother called me Grace because I was anything but graceful. (She also use to tell me that if I didn't stop what I was doing, I was going to skin my ignorance. LOL!)