Your brother-in-law is either the husband of your sister or the brother of your spouse.
Where your brother-in-law is the husband of your sister, there is no relationship name in the English language to describe his brother's relationship to you. However, in that situation your brother-in-law's brother is your sister'sbrother-in-law.
Where your brother-in-law is the brother of your spouse, his brother is also your brother-in-law.
Your brother's wife is your sister-in-law. The English language has no relationship term for the brother of your sister-in-law. He is not considered to be related toyou, although he is your brother's brother-in-law.
Your brother-in-law's wife may be your sister.However, if your bother-in-law is the brother of your spouse, his wife is not your sister and the English language has no special term for her relationship to you. It is easiest to call her "my brother-in-law's wife."
Your mother's brother is your uncle. Your uncle's wife's sister is his sister-in-law. There is no family relationship between you and your uncle's sister-in-law's daughter, unless the sister-in-law is married to someone who is related to you.
If you really need a relationship term, use granddaughter-in-law. Most people would merely say "my grandson's wife."
The English language does not contain a specific term to describe a relationship between you and your nephew's wife. The culture does not consider her to be related to you. Most aunts and uncles would merely call her "my nephew's wife."
Your brother's wife is your sister-in-law. The English language has no relationship term for the brother of your sister-in-law. He is not considered to be related toyou, although he is your brother's brother-in-law.
Your wife's sister's husband is your wife's brother-in-law, but is not related to you.
Aunt
The wife of your brother is your "sister-in-law" In English, this is true whether the brother is older or younger than you are.
Your brother's son is your nephew, but the English language has no term for a relationship between you and the wife of your nephew. If you have to refer to her other than by name, the best you can do is call her "my nephew's wife" or "my brother's daughter-in-law."
The English language has no relationship term for the wife of your cousin's brother. You are not considered to be related to her.
Your brother-in-law's wife may be your sister.However, if your bother-in-law is the brother of your spouse, his wife is not your sister and the English language has no special term for her relationship to you. It is easiest to call her "my brother-in-law's wife."
Your husband's brother is your brother-in-law. The English language has no special term for your relationship to his wife. Most people simply refer to "brother-in-law's wife."Of course, to you husband his brother's wife is his sister-in-law.
Your husband's brother is your brother-in-law. Your brother-in-law's wife is not related to you, but is your husband's sister-in-law. The sister of your husband's sister-in-law is not related to you or to your husband.
Your wife's brother's daughter is her niece and your wife is her niece's aunt. Although you have no genetic relationship to your wife's niece, by convention your wife's niece is considered to be your niece and you are her uncle.
Your ex-sister-in-law is either the ex-wife of your brother or the sister of your ex-spouse. In either case, the English language has not yet developed a term describing her relationship to you.
Brother-in-law