Your sister's son, is your nephew.
He is your nephew
A siblings son is always called a nephew
Your daughter and your sister's son are first cousins to each other.
Uncle or Auntie.
Your sister's son is your nephew and you are his aunt (if you are female) or his uncle (if you are male.
Your sister's son is your nephew.
No, making your son wear his sisters pants is not a good punishment.
55Is not this the carpenter's son? is not his mother called Mary? and his brethren, James, and Joses, and Simon, and Judas? 56And his sisters, are they not all with us?
Bastet had a twin sister Called Sekhmet who later on had a son called Maahes but she did not have any brothers