Your sister's son is your nephew. You are his aunt, if you are
female, or his uncle, if you are male.
Your sisters daughter's son is your great nephew.
Your father's sister is your aunt and her son is your first cousin.
Well, it depends how close you are to your husbands family. If you really want to know they are cousins-in-law.
First cousins, as you share a common grandparent.
Your sister's son is your nephew His sons are your grandnephews, and his daughters are your grandnieces.
Your sisters daygter is your neice!
Your sisters son is your nephew.
Your son would be the uncle of his brother's son.
Your brother's son is your nephew.
your sisters daughter would be your neice and you will be there uncle or aunt if you are a boy or girl
They're second cousins.
Your Uncle's son is your first cousin.
Your son and your niece are first cousins.
Your daughter's son is your grandson and you are his grandparent.
Your uncle's son is your first cousin.