Your grandfather and his sister had children (a first generation), your dad and her child (a second generation). Your dad and that child are first cousins. You are in the third generation and your relation to your dad's first cousin makes you a first cousins once removed because you are in the third generation.
The child of your grandfather's first cousin is your second cousin, once removed.
Your child would call your sister her aunt.Your sister would call your child her niece or nephew depending on gender.Your sister's children would call your child their cousin.
sister friend
Aunt
Aunty and Uncle.
You would call your father's sister "பெரிய அந்தை" (periya anthai) in Tamil.
philapple Uncle
Your half-sister's mother may be your mother, if you have different fathers. If you have different mothers and your father is married to your half-sister's mother, then you probably should call her "mother." If your half-sister's mother is not connected to your father (i.e. her father married your mother) then there is no relationship name for you to call her mother, other than "my half-sister's mother."
NO. And if he does, call the police.
Your cousin
bessy
Great grand aunt.Great grand aunt.Great grand aunt.Great grand aunt.
He would be your grand-nephew.