If you are a woman, you are great great aunt to your niece's granddaughter.
If you are a man, you are great great uncle to your niece's granddaughter.
In either case, your niece's granddaughter is your great great niece.
What relation am I to my niece daughter?
does it make me grand uncle or great grand uncle?
You would be your niece's daughter's great aunt.(:
Your niece'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..
Your wife's niece is also your niece, so you are her uncle.
Your Niece's parents are the Grandparents....So you would be the Grand Aunt or Uncle.
Your aunt's grandchildren would be your first cousins once removed, as the your aunt's children are your first cousins.
Second Cousin
Great-niece.
your niece
Your uncle's granddaughter and your child are second cousins.
You granddaughter is a great great niece of your aunt. Your aunt is your granddaughter's great great aunt.
Nephews and nieces
your 2nd niece...!
Great neice
Your granddaughter and grand niece are second cousins to each other.
Your great nephew and your granddaughter are second cousins to each other.
Your granddaughters and son have the relationship of nieces and uncle. Your granddaughters being his nieces and your son being their uncle.