<P> A nephew is a son of a person's sibling, and a niece is a daughter of a person's sibling . Conversely, that person is the aunt or uncle of their niece or nephew . The gender - neutral term encompassing both nephews and nieces is nibling . The relationship of aunt / uncle to niece / nephew is an example of second - degree relatives, meaning that their coefficient of relationship is 25% . </P> <P> The terms are also used colloquially for sons and daughters of siblings - in - law, even though there is no blood relationship . </P>

Brother's daughter is called as in english