A nephew is the son of one's sibling, which means he is the child of either a brother or a sister. Nephews can be related by blood or through marriage, such as when a person marries someone who has children from a previous relationship. In many cultures, having a nephew can create a special bond, as uncles and aunts often play a significant role in a child's life. They may participate in family gatherings, celebrations, and provide support or guidance, contributing to the child's upbringing and experiences.