Real sister, half sister, or step sister
sister in law.
Your sister's sister is your sister.
No relation whatsoever. You will be an aunt or uncle to your sister's child and your brother-in-law's sister will be the child's aunt, but that's as close as it gets.
Your mothers sister is your Aunt
There is no relation. Your not blood at all so your just really good friends.
sister-in-law
No relation...lol
She would be the same relation to you as she is to him.
Your nephew.
Your sister-in-law's son is your nephew.
None. She is your daughter's sister -in-law.