Your wife's sister is your sister-in-law. You are not related to your wife's sister's husband.
You are not related to all of your brother-in-law's family, but you are related to some of them. You are related to your brother-in-law. You are related to his wife, your sister. If he and your sister have children, you are related to them - they would be your nieces and nephews. But you are not related to your brother-in-law's siblings, cousins, parents, aunts, uncles, grandparents, etc.
Your brother's wife is your sister-in-law, but her sister is not related to you.
Your aunts and uncles are the sisters and brothers of your parents. So they are "blood related." But you also call the husband of your mother's sister your uncle, and he is not "blood related." So aunts and uncles are not always really related to you.
Yes, the sister of your spouse (wife or husband) is your sister-in-law. In addition, the wife of your brother is also your sister-in-law.
Your wife's sister is your sister-in-law. You are her brother-in-law.
Not genetically, they are your aunt as in family but you do not share and blood with them.
Your sister and your wife's sister are not related to each other.
Your wife's brother is your brother-in-law. Your brother-in-law's wife is not related to you, and the same applies to her sister.
Your uncles are the brothers of you mother or father, or the husbands of your parent's sisters.Your dad's sister-in-law could be the sister of his wife, your mother. In that case, her brother is also your mother's brother and is therefore your uncle.However, your dad's sister-in-law could be the wife of his brother. In that case, her brother is your dad's brother-in-law but is not related to you.
No, your wife's sister-in-law may be your sister. Your wife can also have a sister-in-law who is not related to you; that would be the wife of her brother.
Your uncle would be your sons great uncle. Normally your Son would also call him 'Uncle .... '