Great aunt; that is your grandmother's sister. Some people might call it grand aunt, although they might think you are calling them fat. :]
Your great aunt.
Great grand aunt.Great grand aunt.Great grand aunt.Great grand aunt.
you say call me great aunt not grand aunt
Her grand great Aunt.
Your great grandmother's sister is your great great aunt (or some would say, your great grand aunt).
Tía is aunt. Bistía is great aunt or grand aunt.
Her grand great Aunt.
Your grandmother's sister is your great aunt
The aunt of a great grand niece is her aunt - the sister of her mother or father. The great grand niece has a great grand aunt, or great grand uncle, who is the sibling of one of her great grandparents. In normal conversation, such a person would usually be called "Aunt," becasue adding all those "greats" and "grands" is cumbersome and would probably just make her feel old.
He would be your grand nephew; you would be his great-aunt.
Your grand niece's son is your great grand nephew, or, some would say, your great great nephew. You are his great grand aunt or great grand uncle, or, some would say, great great aunt or great great uncle.
If your sister or brother had a grandchild, and you were a woman, you would be a grand aunt to that grandchild. Some people say great aunt, instead of grand aunt.