When your sister-in-law is the sister of your spouse, her sister is also your sister-in-law, unless she is your wife.
When your sister-in-law is the wife of your brother, her sister is not related to you.
If your brother-in-law is your spouse's brother, then his sister's daughter is your spouse's niece, and your niece, too.
If your brother-in-law is your sister's husband, then his sister is not related to you, and neither is her daughter.
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.