Step-great-granddaughter
Your brother's granddaughter is your great niece and you are her great uncle if you are a man, or her great aunt if you are a woman..
Your sister's granddaughter is your great niece and you are her great aunt (if you are a woman) or great uncle (if you are a man).
Your aunt is great great aunt to your son's daughter (your granddaughter). Your granddaughter is your aunt's great great niece.
Your grandfather's brother is your great uncle. Your great uncle's daughter's daughter (his granddaughter) is your second cousin.
Great grandfather in Swahili is "babu mkubwa."
The word is "bisnieta". Note that "nieta" alone means "granddaughter".
Kubwa
Your granddaughter is your brother's grand niece (or some would say, great niece).
Your granddaughter is your brother's grand niece (or some would say, great niece).
oldebarn = great grandchildthere isn't a word for granddaughter or grandson - both are refereed to as 'barnebarn' = grandchild (same goes with 'great ...' -but it's "oldebarn")
You granddaughter is a great great niece of your aunt. Your aunt is your granddaughter's great great aunt.
Example: Great-great-great Granddaughter Katie
Your granddaughter is your sister's great niece. Your sister is your granddaughter's great aunt.
Your sister is her great grandaunt.
Your brothers great granddaughter is your great great niece.
Your brothers granddaughter is your grandniece.