Your nephew's sister is your niece.
Your niece's brother is your nephew.
They are first cousins.
Nephews and/or Nieces
Your brother's wife's kids would be your nieces or nephews.
Your brother's daughters are your nieces
I can give you several sentences.My nieces are coming for a visit.Are those girls your nieces?Nieces are the daughters of your brother or sister.
Nieces.
I have three nieces. One of my nieces has had her hair braided. My other two nieces are jealous of her. My niece's braided hair is a honey-golden brown. My nieces' mother is married to my oldest brother.
If your brother (or your sister) has children they are your nephews (males) and nieces (females).
Your brother-in-law's children are your nephews and nieces.
Your brother's children would be your nieces and nephews.
Your brother's child's children are your grandnieces or grandnephews.
Your brother's daughters are your nieces
It says what relation are your brothers nieces to you.... It could be your child or your niece also causes you can have two brothers and it may be the other ones kids. Or of course it could be your brother's new wife kid by another man making her no relation.