Your great aunt is your daughter's great great aunt. Your daughter is your great aunt's great great niece.
Your great-great aunt is your daughter's great-great-great aunt.
Great Aunt to Great Niece.
Your aunt is great great aunt to your son's daughter (your granddaughter). Your granddaughter is your aunt's great great niece.
You are her great-aunt/uncle. She is your great-niece.
Your great uncle's daughter would be your aunt.
You are the great aunt/uncle
Your nephew's daughter is your great niece. You are her great aunt (if you are a woman) or her great uncle (if you are a man).
Great aunt or uncle.
Your nephew's daughter is your great niece and you are her great aunt (if you are a woman) or her great uncle (if you are a man).
Your grandmother's sister is your daughter's great great aunt. Your daughter is the great great niece of your grandmother's sister.
Your aunt is your daughter's great aunt. Your daughter is your aunt's great niece.
Your niece's daughter is your great niece. You are her great aunt or great uncle, depending on your sex.