Your nephew's wife is your Niece-in-Law, whether she is caring for a child from a previous marriage or not. Few people would care to be that precise, however, so most will probably just call her your Niece.
If your great uncle is the brother of one of your grandparents, his wife is your great aunt but their nephews and nieces onher side are not related to you. Those nieces and nephews (and their children the great nieces and great nephews) have no ancestor who is also one of yourancestors.
The children born to your siblings are your nieces and nephews.
The two most famous nephews of Tiberius were/are Germanicus and Claudius.The two most famous nephews of Tiberius were/are Germanicus and Claudius.The two most famous nephews of Tiberius were/are Germanicus and Claudius.The two most famous nephews of Tiberius were/are Germanicus and Claudius.The two most famous nephews of Tiberius were/are Germanicus and Claudius.The two most famous nephews of Tiberius were/are Germanicus and Claudius.The two most famous nephews of Tiberius were/are Germanicus and Claudius.The two most famous nephews of Tiberius were/are Germanicus and Claudius.The two most famous nephews of Tiberius were/are Germanicus and Claudius.
The wife of the Vice president
niece in-law
Your wife's nephew is your nephew, but the English language has no relationship term for your nephew's wife. Just call her "my nephew's wife."
Your nephew's wife is your Niece-in-Law, whether she is caring for a child from a previous marriage or not. Few people would care to be that precise, however, so most will probably just call her your Niece.
Your sister-in-law is either the wife of your brother or the sister of your spouse. The children of your brother's wife are your nieces and nephews, since they are also the children of your brother. In some cases they may be your sister-in-law's children from a previous marriage. Then they are not related to you at all. However, if they are very young, it may be convenient to call them your nieces and nephews anyway. The children of your spouse's sister are always your nieces and nephews.
Nephews
your nephews
Some would call your nephew's children your grand nephews and grand nieces, others would call then your great nephews and great nieces.
No. Your wife's niece is also your niece, but the husband of the niece is not related to you or to your wife.
your niece's or nephews
if they are the children of your brother, they would be your nephews and nieces - if they were her children before she married your brother, then step-nephew and step-nieces
If it is a boy then it is your nephew. If it is a girl then it is your niece.
nephews!