She is your aunt.
sister friend
Aunt
Aunty and Uncle.
philapple Uncle
sister in law
Your fathers sister or fathers brothers female partner.
Yes
Your father's sister is your aunt. Her son is your first cousin. Her grandson is your first cousin, once removed.
fathers elder brother ANSWER: your sister in law........
Cousins
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."
fathers