Your sister's son is your nephew.
Your son's daughter is your granddaughter.
Your son and your sister's son are first cousins to each other.
Your son's daughter and your sister's son are first cousins once removed to each other.
Your grandchild and your sister's grandshild are second cousins to each other.
Cousine
Your granddaughter and your sister's grandson are second cousins.
Your younger brother's wife's sister's daughter would be your son's cousin.
Yes, she did. She had the relationship of a mother that a mother has with her son. As most mothers do.
They are second cousins
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".
Your son and your nephew are first cousins to each other. Their daughters are second cousins to each other.
Your sister's son is your nephew His sons are your grandnephews, and his daughters are your grandnieces.
Daughter is the opposite of son.
Gandhi had sons, and now grand sons.
Your daughter's son is your other daughter's nephew and she is his aunt.
My sister's son is my nephew.