cousin
3rd cousin
Your grandfather's niece is a first cousin of one of your parents. Her son is your second cousin.
Most likely they would not be related to you
Your grandfathers' sisters' grandchildren are your second cousins.
Your father's sister is your aunt and her son is your first cousin.
Your sister's son is your nephew His sons are your grandnephews, and his daughters are your grandnieces.
Well, it depends how close you are to your husbands family. If you really want to know they are cousins-in-law.
Your grandmother is first cousins with cousin. Your parent would be the second cousin of the cousin's son. That would make you second cousins once removed.
your second nephew
Your sister's son is her grandson and your great nephew. Some use the term "grand nephew."
Yes, along with your grandfathers' sisters, if any.
Your sister's son is your nephew His sons are your grandnephews, and his daughters are your grandnieces.