Great-great-grandmother.
You add another "great" for each generation back in history. So the mother of your great great great grandmother is your great great great great grandmother.
You grandmother's father is your great grandfather and his wife (your grandmother's mother) is your great grandmother.
Your great grandmother's sister is your great-great-aunt.
The English language does not include a relationship called "great mother." It has terms "grandmother" (the mother of your father or of your mother) and great grandmother (the mother of one of your grandparents. The sister of your grandmother is your great aunt. The sister of your great grandmother is your great great aunt.
She could be your grandmother. Or she could be your great aunt.
great grandmother is the correct way to spell it.
The High German for "Great-grandmother" is "Urgroßmutter".The colloquial usage of "Great-grandma" is "Uroma".
If you mean a word for the grandmother of one of your parents, the standard term is great-grandmother. If you want to write the name that you call her, and if you say it as "great-gramma," that spelling is as good as any.
bisabuela
The mother of one of your grandparents is your great-grandmother.The colloquial is "great-grandma" e.g. "Great-grandma Smith."
Your grandmother's grandmother is your great-great-grandmother.
great great grandmother = arrière-arrière grand-mère
Your great grandmother's mother is your great great grandmother.
Tatarabuela Grandmother: abuela Great grandmother: bisabuela Great great grandmother: tatarabuela
The term that comes after "great grandmother" is "great great grandmother." The "great" prefix is added for each additional generation, so it would be "great grandmother 1x" for one generation back and "great great grandmother 2x" for two generations back. Therefore, the correct term is "great great grandmother."
Your father's grandmother is typically referred to as your great-grandmother.
You add another "great" for each generation back in history. So the mother of your great great great grandmother is your great great great great grandmother.