Grand-Nephew
Your sister's son is your nephew and you are his uncle (if you are male) or his aunt (if you are female).
Your sister's son and your daughter are first cousins to each other.
Your sister's son and your daughter's son are first cousins, once removed, to each other.
Your sisters daughter's son is your great nephew.
Grand-Nephew
Great niece
Your sister's son is your nephew His sons are your grandnephews, and his daughters are your grandnieces.
Your sister's son is your nephew His sons are your grandnephews, and his daughters are your grandnieces.
your second nephew
YesThe son and his sister = 1 son, 1 sisterThe sons and their sister = many sons, 1 sisterThe son and his sisters = 1 son, many sistersThe sons and their sisters = many sons, many sistersThough in reality this is a strange way to say it. More normal would be "The sons and daughters".
No, because my father's sister (my aunt) does not have any sons, she only had daughters.
Wat the heck in this question yaar? its maternal uncle. you are uncle your son is first cousin to your sisters his aunt sons or daugters a : a child of one's uncle or aunt b : a relative descended from one's grandparent or more remote ancestor by two or more steps are cousins and when those sons and daughters have kids they become second cousins etc.
Grand-Nephew
cousin
Your son's children are your grandchildren.
My sister's son is my nephew.
cousin
He had 4 daughters and 1 son john Rockefeller jr.