The Yiddish word for great aunt is "גרויסע מוטער" (groys maytel).
The Yiddish word for aunt is "tante." It is pronounced as "tahn-teh."
TanteMume
Hebrew = doda (דודה)Yiddish = Muma (מומע) or Tanta (טאנטע)
flammer boy with an aunt
Your great aunt is your daughter's great great aunt. Your daughter is your great aunt's great great niece.
Your great aunt.
You Aunt is you grandson's Great-Great Aunt. Your grandson is your Aunt's Great-Great Nephew.
You granddaughter is a great great niece of your aunt. Your aunt is your granddaughter's great great aunt.
Fannie is often a nickname or diminuitive for something else. I had an aunt Fannie, who was "FAY-gel" in Yiddish, meaning 'little bird'. Whereas my wife also had an aunt Fannie, who was "FAHN-ya" in Yiddish. That one came from the Polish, of her home town. However, if by "fannie" you mean buttocks, then the word is "tush" or "tushie."
To your child, she would be a great great great aunt. If she is your mother's great aunt, that means she is your great great aunt, making her a great great great aunt to your child. I would just stick to calling her auntie or Aunt ______. :)
Your great-great aunt is your daughter's great-great-great aunt.