brother in law
• brother of the husband, brother of the wife, husband of the sister, husband of the sister of the wife
• your brother-in-law is the brother of your husband or wife, or the man who is married to your sister or to your wife's or husband's sister.
daughter in law
• your daughter-in-law is the wife of your son.
father in law
• your father-in-law is the father of your husband or wife.
mother in law
• your mother-in-law is the mother of your husband or wife.
prospective son in law
• future son-in-law, future husband of one's own daughter
sister in law
• your sister-in-law is the sister of your husband or wife, or the woman who is married to your brother or to your wife's or husband's brother.
son in law
• your son-in-law is the husband of your daughter.