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
Your great aunt.
Great Aunt
your great aunt.
if it is a boy it is a cousin brother and if it is a girl it is a cousin sister
Great great aunt/uncle. To your niece, you are the aunt/uncle, to her child you would be the great aunt/uncle. So you would then be the great great aunt/uncle of her child's child (her grandson)
Your parent's aunt is your great aunt. Your great aunt's daughter's child is her grand child. You and your great aunt's grandchild are second cousins.
grandparentGreat Aunt or Great Uncle
A great aunt or great uncle.
The child of your great aunt and great uncle is the first cousin of one of your parents and your first cousin, once removed.
Your aunt is your child's Great Aunt, so your child is her great niece or great nephew.
The same reason that it is a mother when it is her child and aunt for her sister's children.